Full opinion text
B.D. PARKER, Jr., Circuit Judge. This case, consisting of four actions, addresses whether properties reacquired by the Oneida Indian Nation of New York (“OIN” or “the Oneidas”) are subject to taxation by the City of Sherrill, New York and Madison County, New York. The OIN is a federally recognized Indian tribe, governed by a Nation Representative and a Tribal Council. The Oneidas lived on what became central New York State long before the founding of the United States. In the late eighteenth century most of the Oneidas’ ancestral land was formally set aside by Congress as reservation land. During the nineteenth century much of it was sold to non-members of the tribe. But starting in the 1990s members of the tribe reacquired parcels in open-market transactions, and in 1997 and 1998 the purchases included several businesses and properties in Sherrill. These properties include two upon which the Oneidas operate a gasoline station, a convenience store, and a textile manufacturing and distribution facility (the “Sherrill Properties” or the “properties”). Contending that these properties are within their reservation and are, consequently, not subject to taxation, the Oneidas refused to pay the property taxes or to collect sales taxes on merchandise sold at the businesses. Following this refusal, Sherrill purchased three of the properties at tax sales and, two years later, recorded deeds. Sherrill also started formal eviction proceedings. In response, the Oneidas sued Sherrill in the United States District Court for the Northern District of New York (the “Lead case”), contending that the land, as part of their historic reservation recognized principally by the 1794 Treaty of Canandaigua, is exempt from state and municipal taxation. The suit sought declaratory and injunctive relief prohibiting the evictions and the imposition of property taxes. Although the Sherrill Properties were purchased from non-Oneidas, the Oneidas claim that their purchases reestablished the properties as reservation land because the federal government— which alone has the power to do so — has never changed the reservation status of the land. Sherrill counterclaimed, seeking declaratory and injunctive relief and damages, asserting that, for a variety of reasons, the land had lost its reservation status and that the OIN has been unjustly enriched by municipal benefits received, but not paid for, after reacquisition. Sherrill also petitioned the New York State Supreme Court, Oneida County, to order the eviction of the 0IN from the properties (the “Eviction case”). The OIN, citing federal preemption, removed to federal court, contending that sovereign immunity barred Sherrill’s claims. In response to this defense, Sherrill filed an action against the individual members of the Tribal Council (the “Members case”). Sherrill again sought eviction and also sought injunctive relief, forbidding council members from purchasing additional properties in the city. These three cases were related to an additional action (the “Related case”), brought by the OIN against Madison County, concerning thirteen parcels of land also purchased by the OIN in the 1990s. As in the Lead case, the Oneidas sought declaratory relief that these properties are not subject to taxation, contending that, notwithstanding intervening non-Indian possession, these properties have remained reservation land. Procedural strife followed. In the Lead case, Sherrill moved for summary judgment, for injunctive relief, and to amend its answer to add various affirmative defenses. The OIN opposed the motions and cross-moved for summary judgment in the Lead and Eviction cases, asserting principally that the parcels in question were non-taxable because they were located on reservation land in Indian country. See 18 U.S.C. § 1151. In the Members case, the OIN officers moved to stay or, in the alternative, to dismiss principally on grounds of sovereign immunity and the failure to name the OIN as a party. Madison moved to dismiss the Related case for failure to join two allegedly indispensable parties: the Wisconsin and Thames Oneidas. In November 2000, the State of New York, Madison and Oneida Counties, and a public company, Oneida Ltd., filed briefs as amici curiae in the Lead case in support of Sherrill’s motion for summary judgment and in opposition to the OIN’s cross-motion. After the dust settled, the District Court issued a well-reasoned opinion resolving these various motions. Oneida v. City of Sherrill, 145 F.Supp.2d 226 (N.D.N.Y.2001) (“Oneida IV”). It considered a number of issues but devoted a good deal of attention to what the parties considered— and what we agree — to be the basic question posed: whether the properties are in Indian country. Oneida IV, 145 F.Supp.2d at 241. The court concluded that, for a number of reasons, they are. The properties are part of the Oneidas’ aboriginal lands and federally recognized reservation. The reservation’s status was guaranteed by treaty obligations — principally in the 1794 Treaty of Canandaigua — and Sherrill did not carry its burden of demonstrating congressional action disestablishing the reservation. Accordingly, the District Court concluded that, as they are in Indian country, neither the Sherrill nor Madison Properties are taxable by Sherrill and Madison County, and granted the OIN judgment on its claims in the Lead case. Id. at 254-259. Determining that the OIN was entitled to sovereign immunity, the court also granted judgment on Sherrill’s counterclaims in the Lead case and denied Sherrill leave to amend its complaint. Id. at 258-59. The court granted the OIN judgment in the Eviction case as well, concluding that it was entitled to sovereign immunity. It also granted the council members’ motion to dismiss in the Members case, concluding that they too were entitled to sovereign immunity and that, in any event, Sherrill had failed to join the OIN, which the court found to be an indispensable party. Finally, the court sua sponte granted the OIN judgment on the pleadings in the Related case, concluding that its findings with respect to the Sherrill Properties applied also to those located in Madison. Separately, the court denied Madison County’s motion to dismiss that case. Oneida Indian Nation of N.Y. v. Madison County, 145 F.Supp.2d 268, 270-71 (N.D.N.Y.2001). Sherrill and Madison appealed. We agree with the District Court’s principal conclusion that the OIN’s Sherrill Properties are not taxable, and therefore affirm the judgment in the Lead, Eviction, and Members cases. Because we find, however, that the court’s sua sponte grant of judgment on the pleadings in the Related case was procedurally improper, we vacate this judgment and remand for further proceedings. BACKGROUND I. Treaties Governing Rights to the OIN’s Land Since the land in question has been the subject of federal litigation off and on for more than one hundred and fifty years, before looking at the controlling legal issues, we briefly review how we reached this point in time. As previously noted, the parties contest whether land first occupied by the Oneidas in upstate New York before the founding of this country is, upon reacquisition by the Oneidas, subject to taxation by New York State and its municipalities. The Oneidas are the direct descendants of members of the original Oneida Indian Nation, one of the six nations of the Iroquois Confederacy (the “Six Nations”), which were the most powerful Indian tribes in the northeastern United States at the time of the American Revolution. County of Oneida, N.Y. v. Oneida Indian Nation of N.Y., 470 U.S. 226, 230, 105 S.Ct. 1245, 84 L.Ed.2d 169 (1985) (“Oneida II”) (citing B. Graymont, The Iroquois in the American Revolution (1972)). The Six Nations are the Cayugas, Mohawks, Oneidas, Onondagas, Senecas, and Tuscaroras. New York Indians, 170 U.S. 1, 36, 18 S.Ct. 531, 42 L.Ed. 927 (1898) (“New York Indians II”). From time immemorial through the Revolutionary period, the Oneidas inhabited what is now central New York State. Their aboriginal lands covered approximately six million acres, from the Pennsylvania border to the St. Lawrence River, and from the shores of Lake Ontario to the western foothills of the Adirondack Mountains. Oneida II, 470 U.S. at 230, 105 S.Ct. 1245. A. Nonintercourse Act and Canandaig-ua Treaty With the adoption of the Constitution, Indian relations came exclusively under federal authority. See Oneida II, 470 U.S. at 234, 105 S.Ct. 1245; Oneida Indian Nation of N.Y. v. New York, 194 F.Supp.2d 104, 146 (N.D.N.Y.2002) (Oneida IIIb) (“[A]ny rights [in Indian land] possessed by the State prior to ratification of the Constitution were ceded by the State to the federal government by the State’s ratification of the Constitution.”). Article I, section 8, clause 3 of the Constitution, the Indian Commerce Clause, established Congress’s power “[t]o regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes.” U.S. Const., art. I, § 8, cl. 3. In 1790, Congress passed the first Indian Trade and Intercourse Act (the “Nonin-tercourse Act”), 1 Stat. 137, sharply limiting the alienability of Indian land. In essence, the Nonintercourse Act required federal consent for all land purchases from Indian nations. The 1793 amendments to the Act, which contain the language currently in effect, provided: No purchase, grant, lease, or other conveyance of lands, or of any title or claim thereto, from any Indian nation or tribe of Indians, shall be of any validity in law or equity, unless the same be made by treaty or convention entered into pursuant to the Constitution. Act of March 1, 1793, 1 Stat. 329 (1793) (codified at 25 U.S.C. § 177 (2000)); see generally Mohegan Tribe v. Connecticut, 638 F.2d 612, 616-18 (2d Cir.1980) (discussing history of and amendments to Nonintercourse Act). The Supreme Court has consistently applied the principle, embodied in the Nonin-tercourse Act, that federal consent is required for purchases of Indian land or for the termination of aboriginal title. See, e.g., Oneida II, 470 U.S. at 232, 105 S.Ct. 1245; United States v. Santa Fe Pacific R. Co., 314 U.S. 339, 345, 62 S.Ct. 248, 86 L.Ed. 260 (1941) (“Unquestionably it has been the policy of the Federal Government from the beginning to respect the Indian right of occupancy, which could only be interfered with or determined by the United States.”) (citing, among other authorities, Johnson v. McIntosh, 8 Wheat. 543, 5 L.Ed. 681 (1823) (refusing to recognize land titles originating in grants by Indians to private parties in 1773 and 1775 because they were contrary to principle that Indian title could only be extinguished by or with consent of federal government)). The absence of federal consent is the Oneidas’ central argument in this litigation. Another pivotal enactment was the 1794 Treaty of Canandaigua, 7 Stat. 44 (Nov. 11, 1794). This treaty recognized that the Oneida reservation covered approximately 300,000 acres, and the federal government undertook that it “[would] never claim [this land], nor disturb [the Oneidas] ... in the free use and enjoyment thereof: but the said reservations shall remain theirs, until they choose to sell the same to the people of the United States, who have the right to purchase.” 7 Stat. 45. On the strength of this treaty, which, remains in force, the Oneidas contend that the land in Madison and Sherrill is reservation land in Indian country and, upon reacquisition, must be treated as such. B. Indian Removal and the Treaty of Buffalo Creek Notwithstanding the Nonintercourse Act’s prohibition on purchases of Indian land, and despite federal government advice to the contrary, New York State repeatedly purchased Indian land within its borders. In a 1795 transaction, for instance, the OIN conveyed virtually all of its remaining land to New York in exchange for annual cash payments. Oneida II, 470 U.S. at 232, 105 S.Ct. 1245. Overall, more than thirty treaties of purchase were made with various segments of the tribe during the late eighteenth and early nineteenth centuries. See Jack Campisi, Oneida, in 15 Handbook of North American Indians 484 (Bruce G. Trigger ed., 1978) (hereinafter “Campisi”). The Madison properties purportedly were conveyed to the State in this manner. As Oneida lands were transferred to the State, they were surveyed and laid out in townships, which eventually were subdivided and sold to private parties. Individual Oneidas also sold land to private parties. The Sherrill Properties fall into this group of conveyances. The Oneidas contend that tó the extent any of the purchases lacked congressional approval, they violated the Non-intercourse Act and the Treaty of Canan-daigua. . Early in the nineteenth century, federal policy concerning eastern Indians changed from maintenance of their right of occupancy in ancestral lands to their removal west of the Mississippi River. This change was spurred by the states’ desire to control the remaining unceded Indian land within their boundaries, by the incursion of settlers onto treaty-protected Indian land, and by the perceived inability of the Indians to assimilate. See David H. Getches et al., Cases and Materials on Federal Indian Law 93-95 (4th ed.1994) (hereinafter “Getches”); Felix S. Cohen, Handbook of Federal Indian Law 53-54 (1942) (hereinafter “Cohen”). Removal was deemed necessary to “mak[e] available for white settlement a vast area and solving the problem of conflict of authority caused by a presence of Indian nations within state boundaries.” Cohen at 53. Between 1810 and 1816, the Six Nations, facing pressure from New York State to remove, purchased approximately 500,000 acres in Wisconsin from the Menominee and-Winnebago tribes. New York Indians II, 170 U.S. at 11-14, 18 S.Ct. 531. Several hundred Oneidas moved there during the 1820s, with only a small number remaining in New York. Id. at 14, 36, 18 S.Ct. 531; United States v. Boylan, 265 F. 165, 167 (2d Cir.1920); Campisi at 485. Those who stayed “held a single and undivided tract reserved out of the original Oneida reservation.” Boylan, 265 F. at 167. In 1830, Congress passed the Indian Removal Act, which reflected this shift in federal policy and allowed Indians to exchange their eastern lands for lands set aside in the west. See Act of May 28, 1830, 4 Stat. 411. The Act provided: That it shall and may be lawful for the President of the United States to cause so much of any territory belonging to the United States, west of the river Mississippi, not included in any state or organized territory, and to which the Indian title has been extinguished, as he may judge necessary, to be divided into a suitable number of districts, for the reception of such tribes or nations of Indians as may choose to exchange the lands where they now reside, and remove there .... Ch. 148, 4 Stat. at 411-12 The 1838 Treaty of Buffalo Creek, 7 Stat. 550 (Jan. 15, 1838), was enacted pursuant to this removal policy. Prucha at 202. Stimulated by the desire of Buffalo city leaders to “make room for the expansion of the city onto adjacent Seneca reservation lands,” New York began a “full-scale drive ... to eliminate the Indians from the state and move them to lands west of Missouri.” Id. Under the Treaty, the Six Nations and the St. Regis Indians agreed to remove from their New York and Wisconsin reservation lands to approximately 1.8 million acres in Kansas, which had been set aside as Indian territory. The Treaty provided that the new reservation lands were to provide “a permanent home for all the New York Indians, now residing in the State of New York, or in Wisconsin, or elsewhere in the United States, who have no permanent homes.” Buffalo Creek Treaty, art.- 2. The Treaty authorized a payment of $400,000 to cover the costs of removal. As discussed below, Sherrill and Madison claim that it effected the disestablishment of the Oneidas’ reservation and the formal relinquishment, with congressional approval, of their possessory claim to the lands at issue. The first eight articles and Article 15 of the Treaty set forth this basic bargain. Id., arts. 1-8, 15. Articles 9 through 14 reflect specific agreements between the government and individual tribes. Id., arts. 9-14. In Article 10, for example, the Senecas agreed to remove within five years to land in eastern Kansas, and the government approved the sale of their remaining New York land to two individuals, Thomas L. Ogden of the Ogden Land Company and Joseph Fellows. Id., art. 10; see New York Indians, 72 U.S. (5 Wall.) 761, 767, 18 L.Ed. 708 (1867) (“New York Indians I”). The Tuscaroras made a similar removal commitment in Article 14, which also confirmed the sale of their New York land to Ogden and Fellows. Buffalo Creek Treaty, art. 14. At the time of the Treaty, only approximately 5000 of the original 300,000 acres of Oneida reservation land remained in their hands, the rest having been sold to New York or to private parties. Around 620 Oneidas still resided in New York. Buffalo Creek Treaty, Sch. A, Add. 29. Article 13 of the Treaty provided for the removal of these Oneidas, but only upon certain conditions: The United States will pay the sum of four thousand dollars, to be paid to Bap-tista Powlis, and the chiefs of the first Christian party residing at Oneida, and the sum of two thousand dollars shall be paid to William Day, and the chiefs in securing the Green Bay country, and the settlement of a portion thereof; and they hereby agree to remove to their new homes in the Indian territory, as soon as they can make satisfactory arrangements with the Government of the State of New York for the purchase of their lands at Oneida. Buffalo Creek Treaty, art. 13 (emphasis added). The wholesale removal of the New York Indians to Kansas contemplated by the Treaty never occurred. See New York Indians II, 170 U.S. at 26-27, 18 S.Ct. 531 (noting that provision was only made for the “actual removal of more than about 260 individuals of the claimant tribes,” and that none of the thirty two Indians who actually received Kansas allotments ever settled permanently there). For their part, the Oneidas residing in New York and Wisconsin refused to relocate to Kansas. See New York Indians II, 170 U.S. at 9-10, 18 S.Ct. 531. Hundreds of New York Oneidas moved instead to Wisconsin and to Ontario, Canada. By 1848 only approximately 200 Oneidas resided in New York. Campisi at 485. Thus, by the middle of the nineteenth century, three distinct bands of the tribe existed: the New York Oneidas, the Wisconsin Oneidas, and the Canadian (“Thames”) Oneidas. Oneida IV, 145 F.Supp.2d at 235. The record does not reflect any large block sales of reservation land to New York State by the Oneidas after 1842, when 1100 acres were conveyed. But as the exodus of members continued over the next half-century, reservation acreage inhabited by Oneidas shrank significantly, by some accounts to less than 100 acres. See Boylan, 265 F. at 165 (discussing action brought by federal government, on behalf of Oneidas, seeking ejectment of defendants from thirty-two acres of land, forming part of original Oneida reservation); Annual Report, Commissioner of Indian Affairs, 1890, 1893 (stating that the Oneida reservation contained only approximately 350 acres in 1890, and approximately 100 acres in 1893 when the tribe’s New York branch itself numbered less than 200). II. Land Claims Involving the OIN Litigation involving the OIN and other New York Indians followed the Treaty of Buffalo Creek. Ogden and Fellows, who held fee title to Seneca lands under the Treaty, sued New York to void pre-removal tax assessments after the parcels had been sold to third parties because of the Senecas’ nonpayment of state taxes. New York Indians I, 72 U.S. at 764-65. In 1867, the Supreme Court held that the taxation of the parcels was “premature and illegal” because it interfered with the Indians’ possessory rights guaranteed by the federal government. “Until the Indians have sold their lands, and removed from them in pursuance of the treaty stipulations, they are to be regarded as still in their ancient possession, and are in under their original rights, and entitled to the undisturbed enjoyment of them.” Id. at 770. As noted, most of the Six Nations Indians did not remove to Kansas. The federal government disposed of the Wisconsin lands conveyed to it by the Indians, appropriated the unoccupied Kansas land and placed it in the public domain for sale to settlers. New York Indians II, 170 U.S. at 4, 24, 18 S.Ct. 531. The New York Indians sued, claiming entitlement to the Kansas lands ceded to them under the Treaty, and seeking the value of the land sold and the money the government had agreed to pay on their removal. Id. at 1-2, 18 S.Ct. 531. Eventually the case reached the Supreme Court, which held in 1898 that the Buffalo Creek Treaty effected a present grant of the Kansas lands to the Indians and that forfeiture of these lands could occur only through legislative action. Simply opening the land to settlement, as the federal government had done, was insufficient. Accordingly, the Court concluded that the New York Indians, including the Oneidas, were entitled to money damages. Id. at 25-36, 18 S.Ct. 531. Litigation involving the Oneidas’ proprietary rights in their New York reservation lands began in the late nineteenth century. In 1885, some Oneidas conveyed reservation parcels to non-Indians but continued to live on the land. After the Indian occupants failed to meet mortgage obligations, the owner brought a foreclosure action and, following partition, the Indians were ejected. Reaffirming the principles embodied in the Nonintercourse Act, we held the ejectment improper because the original conveyance lacked the approval of the federal government: the “tribe could not sell, nor the individual members, for they have not an undivided interest in the tribal lands, nor alienable interest in any particular tract.” Boylan, 265 F. at 174. We emphasized that “[a] transfer of the allotment to [non-Indians] is not simply a violation of the proprietary rights of the Indians; it violates the government rights of the United States.” Id. at 173. Many decades later, in 1970, the Oneidas sued Oneida and Madison Counties as a consequence of their occupation of an approximately 900-acre tract ceded by the OIN to New York in 1795. The Oneidas claimed that the occupation violated the Nonintercourse Act and sought to recover the land’s fair rental value for a two-year period in the 1960s. The case reached the Supreme Court, which again affirmed the Oneidas’ aboriginal possessory rights, concluding that the Nonintercourse Act and certain treaty obligations prohibited termination of these rights without federal approval. See Oneida Indian Nation of N. Y. v. County of Oneida, 414 U.S. 661, 675-78, 94 S.Ct. 772, 39 L.Ed.2d 73 (1974) (“Oneida /”) (stating that the Oneidas had asserted “the not insubstantial claim that federal law now protects, and has continuously protected from the time of the formation of the United States, possessory rights to tribal lands, wholly apart from the application of state law principles which normally and separately protect a valid right of possession”). On remand, the district court found the counties liable to the Oneidas, and we affirmed. Oneida Indian Nation of N.Y. v. County of Oneida, 719 F.2d 525 (2d Cir.1983). Hearing the case for a second time, the Supreme Court again affirmed, holding that the Oneidas could maintain a federal common law action based on the counties’ allegedly illegal occupation of their lands and that the Nonintercourse Act did not preempt the tribe’s claims. Oneida II, 470 U.S. at 236-40, 105 S.Ct. 1245. The watershed decisions in Oneida I and Oneida II established the OIN’s right to challenge the deprivation of its historic title by the sales to New York in the late eighteenth and early nineteenth centuries. In 1974, the OIN and the Wisconsin Oneidas brought a similar suit against Oneida and Madison Counties, but of considerably greater scope. The Oneidas alleged that between 1795 and 1846, pursuant to some thirty agreements, New York State illegally acquired approximately 250,000 acres of Oneida reservation land in violation of the Nonintercourse Act. See Oneida Indian Nation of N.Y. v. County of Oneida, N.Y., 199 F.R.D. 61, 66 & n. 8 (N.D.N.Y.2000) (“Oneida IIIa”). The case was inactive during the pendency of Oneida I and II. In 1998, the United States intervened and joined the Oneidas in moving to add as defendants approximately 20,000 private landowners whom the Oneidas claimed were either liable for money damages or should be ejected. In September 2000, the district court concluded, following Oneida II, that the Oneidas could sue state entities for damages based on the illegal occupation of their historic reservation land but that ejectment and money damages from the individual landowners was not available, and the court declined to permit their joinder. See Oneida IIIa, 199 F.R.D. at 79-94. In 1978 and 1979, the Oneidas also challenged New York State’s purchases of their aboriginal lands in 1785 and 1788, under the Treaties of Fort Herkimer and Fort Schuyler, as violations of the Articles of Confederation, the Treaty of Fort Stan-wix, and the 1783 Proclamation. We concluded, however, that the State had the right to make such purchases during the confederal period and dismissed the action. See Oneida Indian Nation of N.Y. v. New York, 860 F.2d 1145 (2d Cir.1988). The next major litigation to reach our court was this group of consolidated cases where, as we have seen, the District Court granted summary judgment to the OIN, determining that the Sherrill and Madison Properties remained reservation land immune from local taxation. DISCUSSION We review the grant of a motion to dismiss or a motion for summary judgment de novo, drawing all reasonable inferences in favor of the nonmoving party. See Chambers v. Time Warner, 282 F.3d 147, 152 (2d Cir.2002); Young v. County of Fulton, 160 F.3d 899, 902 (2d Cir.1998). In reviewing a dismissal pursuant to Federal Rule of Civil Procedure 12(b)(6), we accept as true all material facts alleged in the complaint. Chambers, 282 F.3d at 152. “Dismissal is inappropriate unless it appears beyond doubt that the plaintiff can prove no set of facts which would entitle him or her to relief.” Id. (citation and internal quotation marks omitted). We apply this same standard in reviewing a grant of judgment on the pleadings pursuant to Rule 12(c). Burnette v. Carothers, 192 F.3d 52, 56 (2d Cir.1999). Summary judgment is appropriate if there are no genuine issues of material fact and the movant is entitled to judgment as a matter of law. Fed.R.Civ.P. 56(c). I. Basic Principles Three basic principles inform the disposition of this action. The first is the Indians’ right of occupancy on tribal land, or “Indian country,” which “may extend from generation to generation, and will cease only by dissolution of the tribe, or their consent to sell to the party possessed of the right of pre-emption.” New York Indians I, 72 U.S. at 771. The second, embodied by the Nonintercourse Act, is federal preeminence over the disposition of land in Indian country. Since “Congress alone has the right to say when the [United States’] guardianship over the Indians may cease,” Boylan, 265 F. at 171, the sale or conveyance of reservation land can only be made with congressional sanction, that is, “by treaty or convention entered into pursuant to the Constitution.” 25 U.S.C. § 177 (2000). The third is federal preemption, which prohibits states from imposing property taxes upon Indian reservation land without congressional approval. New York Indians I, 72 U.S. at 771; see also Merrion v. Jicarilla Apache Tribe, 455 U.S. 130, 137, 102 S.Ct. 894, 71 L.Ed.2d 21 (1982) (“The power to tax is an essential attribute of Indian sovereignty because it is a necessary instrument of self-government and territorial management.”); cf. Boylan, 265 F. at 170. There is no material dispute that the Sherrill Properties were part of the Oneidas’ aboriginal land and the tribe’s reservation as recognized by the Treaty of Can-andaigua. Sherrill contends, however, that because the properties are no longer within Indian country and the Oneidas no longer exist as a tribe, they are subject to taxation. We first address these contentions and then turn to the District Court’s procedural rulings. II. Indian Country In general, “Indian country” refers to the geographic area in which tribal and federal laws normally apply and state laws do not. Section 1151 of Title 18 of the United States Code, defining “Indian country,” provides: The term “Indian country” ... means (a) all land within the limits of any Indian reservation under the jurisdiction of the United States Government, notwithstanding the issuance of any patent, and, including rights-of-way running through the reservation, (b) all dependent Indian communities within the borders of the United States whether within the original or subsequently acquired territory thereof, and whether within or without the limits of a state, and (c) all Indian allotments, the Indian titles to which have not been extinguished, including rights-of-way running through the same. 18 U.S.C. § 1151 (2000). Dependent Indian communities encompass any “area ... validly set apart for the use of the Indians as such, under the superintendence of the Government.” Okla. Tax Comm’n v. Citizen Band Potawatomi Indian Tribe, 498 U.S. 505, 511, 111 S.Ct. 905, 112 L.Ed.2d 1112 (1991). Indian allotments are those parcels allocated to tribes, as opposed to those opened to settlers, under federal policies designed to accommodate the westward movement of settlers and to promote the integration of Indians into the wider society. See generally Cass County, Minn. v. Leech Lake Band of Chippewa Indians, 524 U.S. 103, 106-07, 118 S.Ct. 1904, 141 L.Ed.2d 90 (1998) (discussing federal allotment policy). Under § 1151, “[o]nce a reservation has been established, or a dependent Indian community shown to exist, it will remain Indian country until terminated by Congress, irrespective of the nature of the land ownership.” Robert N. Clinton, Criminal Jurisdiction Over Indian Lands: A Journey Through a Jurisdictional Maze, 18 Ariz. L. Rev. 503, 513 (1976). As noted, land in Indian country, including reservation land, is not subject to state taxation absent express congressional authorization. “The treaties and laws of the United States contemplate the Indian territory as completely separated from that of the states; and provide that all intercourse with them shall be carried on exclusively by the government of the union.” Worcester v. Georgia, 31 U.S. 515, 557, 6 Pet. 515, 8 L.Ed. 483 (1832); see also White Mountain Apache Tribe v. Bracker, 448 U.S. 136, 151, 100 S.Ct. 2578, 65 L.Ed.2d 665 (1980); Montana v. Blackfeet Tribe of Indians, 471 U.S. 759, 765, 105 S.Ct. 2399, 85 L.Ed.2d 753 (1985) (“[T]he Court consistently has held that it will find the Indians’ exemption from state taxes lifted only when Congress has made its intention to do so unmistakably clear.”); McClanahan v. Ariz. State Tax Comm’n, 411 U.S. 164, 173-81, 93 S.Ct. 1257, 36 L.Ed.2d 129 (1973); Mescalero Apache Tribe v. Jones, 411 U.S. 145, 148, 93 S.Ct. 1267, 36 L.Ed.2d 114 (1973). “The policy of leaving Indians free from state jurisdiction and control is deeply rooted in the Nation’s history.” Rice v. Olson, 324 U.S. 786, 789, 65 S.Ct. 989, 89 L.Ed. 1367 (1945). It traces from the “doctrine of discovery,” the law of Indian land tenure which the Supreme Court developed in the early nineteenth century to reflect European policy toward the Indians and to explain Indian sovereignty relative to colonial authority. See Johnson v. McIntosh, 21 U.S. (8 Wheat.) 543, 572-74, 5 L.Ed. 681 (1823). The doctrine provided that the “discovering” European nations (and later the United States) held fee title to Indian aboriginal lands, subject to the Indians’ right of occupancy and use. Oneida II, 470 U.S. at 234. As a result, no one could purchase Indian land or otherwise terminate aboriginal title without the consent of the discovering nation’s sovereign. Id. As Chief Justice Marshall explained in Johnson v. McIntosh: In the establishment of these relations, the rights of the original inhabitants were, in no instance, entirely disregarded; but were necessarily, to a considerable extent, impaired. They were admitted to be the rightful occupants of the soil, with a legal as well as just claim to retain possession of it, and to use it according to their own discretion; but their rights to complete sovereignty, as independent nations, were necessarily diminished, and their power to dispose of the soil at their own will, to whomsoever they pleased, was denied by the original fundamental principle, that discovery gave exclusive title to those who made it. Johnson, 21 U.S. (8 Wheat.) at 574. Generally speaking, nineteenth and twentieth century federal policy was consistent with this approach to Indian sovereignty, despite a notably inconsistent vision of the Indians’ relationship to non-Indian citizens. While the tribes exercise inherent sovereign authority over their members and land located within state boundaries, they are nevertheless “domestic dependent nations” under federal protection. Cherokee Nation v. Georgia, 30 U.S. 1, 17, 5 Pet. 1, 8 L.Ed. 25 (1831); see also Boylan, 265 F. at 172. The land they occupy is owned by the United States, which has retained the authority to regulate conveyances. As we have observed, “[w]hile the state[s] ha[ve] a right to make treaties with the Indians, [they] cannot interfere with the right[s] and obligations of the federal government.” Boylan, 265 F. at 173. Although Indians’ dependent status prohibits domestic and international political recognition, “it does assure them self-government, free of most state law strictures, over their territory and members, and, to a more limited extent, over non-Indians.” Getches at 373-74; see Boylan, 265 F. at 174. This “platonic notion[] of sovereignty,” embodied in the so-called “Indian sovereignty doctrine,” historically gave state law “no role to play” within a tribe’s territorial boundaries. McClanahan, 411 U.S. 164, 168, 172, 93 S.Ct. 1257, 36 L.Ed.2d 129 (1973). While courts have moved towards reliance on firmer, more textually based concepts such as federal preemption to definitively resolve the rights of Indian tribes vis-a-vis the states, see id., the Indian sovereignty doctrine remains relevant because it provides a backdrop against which the applicable treaties and federal statutes must be read. A. Set Aside and Superintendence Sherrill contends that, even accepting the proposition that the properties are located within the Oneida reservation’s historic boundaries, the parcels are taxable because they are not currently located within Indian country. Principally relying on Alaska v. Native Village of Venetie Tribal Gov% 522 U.S. 520, 118 S.Ct. 948, 140 L.Ed.2d 30 (1998), Sherrill asserts that the properties are not in Indian country because they were neither set aside by the federal government for Indian use nor placed under federal superintendence. Rather, the properties were acquired in private, open-market transactions and receive services from Sherrill, not the federal government. In Alaska, the Supreme Court considered whether certain nonreservation land owned by members of the Venetie tribe in fee simple was located in Indian country. Id. at 527, 118 S.Ct. 948. The land had been part of the Neets’aii Gwich’in reservation, which had been disestablished pursuant to the Alaska Native Claims Settlement Act, 43 U.S.C. §§ 1601 et seq. Title was then conveyed to the Venetie native corporations as tenants in common, which in turn transferred title to the tribe. Id. at 524, 118 S.Ct. 948. Because the reservation had been disestablished, and because no allotments were involved, “whether the Tribe’s land is Indian country depended] on whether it f[e]ll[ ] within the ‘dependent Indian communities’ prong of the statute, § 1151(b).” Id. at 527, 118 S.Ct. 948. The Court concluded that the land was not Indian country because it neither had been “set aside by the Federal Government for the use of the Indians as Indian land” nor was “under federal superintendence” — two requirements, the Court found, that applied equally to reservations, dependencies, and allotments. Id. at 527, 532-34, 118 S.Ct. 948. Sherrill argues that because the OIN, like the Venetie, purchased the properties in fee and can freely alienate them, the land cannot be in Indian country. We disagree. While questions may arise as to whether nonreservation property owned by Indians is in Indian country, there are no such questions with regard to reservation land, which by its nature was set aside by Congress for Indian use under federal supervision. See United States v. John, 437 U.S. 634, 638-47, 98 S.Ct. 2541, 57 L.Ed.2d 489 (1978) (holding that tribe’s fee simple parcels on historic reservation were under federal control despite the fact that federal supervision of the tribe had not been continuous); cf. Donnelly v. United States, 228 U.S. 243, 269, 33 S.Ct. 449, 57 L.Ed. 820 (1913) (holding that reservation land is Indian country). Because the Sherrill Properties are located on the Oneidas’ historic reservation land set aside for the tribe under the Treaty of Canandaigua, they satisfy the set aside and superintendence requirements of 18 U.S.C. § 1151. Moreover, just as Alaska concluded that the “mere provision” of federal services on the tribe’s property did not make it Indian country, the provision of certain state services to the Oneidas by Sherrill does not eliminate that status. See Alaska, 522 U.S. at 534, 118 S.Ct. 948. B. Alienability Alternatively, Sherrill argues that the properties are not in Indian country because they are freely alienable. Relying on Cass County, Sherrill contends that the reacquisition of freely alienable, former reservation land by an Indian tribe “does not cause the land to resume tax-exempt status ... unless and until [it is] restored to federal trust protection under [25 U.S.C. § 465].” Sherrill Br. at 35 (quoting Cass County, 524 U.S. at 115, 118 S.Ct. 1904). Cass County, however, offers Sherrill little help. There, Congress explicitly had made land in Indian country freely alienable by providing for the “complete cession and relinquishment” of all tribal title in Minnesota. Cass County, 524 U.S. at 108, 118 S.Ct. 1904. After-wards, the land had been subject to federal allotment and sold to non-Indians. Because “alienability equals taxability,” the Court found the land in question to be taxable. Id. at 109, 113, 118 S.Ct. 1904 (citing County of Yakima v. Confederated Tribes & Bands of Yakima Nation, 502 U.S. 251, 112 S.Ct. 683, 116 L.Ed.2d 687 (1992); Goudy v. Meath, 203 U.S. 146, 27 S.Ct. 48, 51 L.Ed. 130 (1906)). In contrast, the Sherrill Properties are located on reservation land, a status which Congress has never changed. Since Congress has not done so, the properties did not become freely alienable and taxable simply because the OIN purchased them on the open market and currently holds them in fee simple. See Solem v. Bartlett, 465 U.S. 463, 471, 104 S.Ct. 1161, 79 L.Ed.2d 443 (1984) (“Once a block of land is set aside for an Indian reservation and no matter what happens to the title of individual plots within the area, the entire block retains its reservation status until Congress explicitly indicates otherwise”)- State and local governments may not tax reservation land “[a]bsent cession of jurisdiction or other federal statutes permitting it.” County of Yakima, 502 U.S. at 258, 112 S.Ct. 683. Sherrill can point to neither. Sherrill is troubled by the seeming “impossibility” that the Oneidas’ free-market purchase of land within their ancient ancestral homeland could instantly render the parcels free from taxation and by the potential hardship to local municipalities and residents resulting from the Oneidas’ “recreation]” of “a tribal homeland.” Sherrill Br. at 87. It suggests that this result is inconsistent with the conclusion of other courts that, even when a reservation has not been disestablished, Indians who no longer own parcels on the reservation cannot base claims to possessory rights on the Nonintercourse Act. Id. at 32-34 (citing Oneida IIIa; Cayuga Indian Nation v. Cuomo, Nos. 80-CV-930, 80-CV-960, 1999 WL 509442 (N.D.N.Y. July 1, 1999)). But there is no inconsistency. The authorities Sherrill points to address the judicial remedies available for interference with the possessory rights of Indian plaintiffs, not the existence of those rights. In Yankton Sioux Tribe of Indians v. United States, 272 U.S. 351, 357-59, 47 S.Ct. 142, 71 L.Ed. 294 (1926), for example, the Supreme Court held that the proper remedy for the wrongful taking of Indian land that was subsequently settled and developed was monetary damages rather than repossession by the tribe. This principle became known as the “impossibility” doctrine because it was based on the impracticability of uprooting current property owners where Indians held a valid possessory claim to land on which others had settled. Our case is different. Recognizing the Oneidas’ possessory rights in their historic reservation land, and the accompanying exemption from state taxation, does not require uprooting current property owners, because the Oneidas currently own the properties in question. Consequently, the threat from eviction present in Oneida Ilia and Cayuga is not present here. And Sherrill’s argument that the removal of property from local tax rolls is a “hardship” that “upsets settled expectations” only begs the question whether the city is authorized to tax the properties. The critical dichotomy, which Sherrill does not acknowledge, is between historic Indian title and fee ownership of the land itself. Indian or aboriginal title is the right of a tribe to use and occupy lands it has inhabited from time immemorial. See Oneida II, 470 U.S. at 234, 105 S.Ct. 1245. When a reservation has been disestablished, as in Alaska or Cass County, Indian title is extinguished and the only pertinent inquiry for ownership purposes is fee title. But when Indian land has been alienated in ways inconsistent with federal law, Indian title remains with the tribe. The Indian-country status of the alienated land is irrelevant for tax purposes when non-Indians hold fee title, since they pay state taxes. But when the tribe holding Indian title reacquires former reservation land, both forms of title coexist. Cf. United States v. Sandoval, 231 U.S. 28, 48, 34 S.Ct. 1, 58 L.Ed. 107 (1913) (rejecting position that Indian lands held in fee simple by Pueblo cannot be Indian country). The Indian-country status of the land therefore becomes fully relevant: the state cannot tax it and the tribe can no longer legally alienate it, at least without federal approval. At first glance, this “coexistence” of titles appears uneasy, because the validity of the Oneidas’ Indian title depends on a finding that the properties were alienated in violation of the Nonintercourse Act. And if this is so, then the chain of fee simple title, of which the Oneidas are now part, is invalid. This unease is ultimately unwarranted, however, because the OIN’s pos-sessory rights are grounded in its unextin-guished Indian title, just as they were prior to the 1805 conveyance. Acquisition of the properties, as the tribe asserts, was the least disruptive means of effectuating these possessory rights. Because the previous fee owners relinquished any claims to the land, the OIN’s rights may be fully realized. Accordingly, we conclude that the OIN’s purchase of the Sherrill Properties in fee simple neither rendered them freely alienable nor deprived them of their Indian-country status. III. Effect of the Buffalo Creek Treaty on Oneida’s Property Rights Both of Sherrill’s arguments for why the properties are not in Indian country rest on the claim that the land is no longer in an Indian reservation. This claim is grounded in the 1838 Buffalo Creek Treaty which, Sherrill and the amici contend, formally disestablished the Oneida reservation. Again, we disagree. Before returning to the text of this treaty, it is helpful to note certain basic canons of Indian treaty construction. A. Canons of Indian Treaty Construction Treaties are generally more closely linked to the historical events surrounding their negotiation and passage than are private agreements. They are, accordingly, “construed more liberally ..., and to ascertain their meaning we may look beyond the written words to the history of the treaty, the negotiations, and the practical construction adopted by the parties.” Choctaw Nation of Indians v. United States, 318 U.S. 423, 431-32, 63 S.Ct. 672, 87 L.Ed. 877 (1943). This is particularly true with regard to Indian treaties. “ ‘The canons of construction applicable in Indian law are rooted in the unique trust relationship between the United States and the Indians [with respect to tribal lands],’ and the Indians’ unequal bargaining power when agreements were negotiated.” Hagen, 510 U.S. at 423 n. 1, 114 S.Ct. 958 (Blackmun, J. dissenting) (quoting Oneida II, 470 U.S. at 247, 105 S.Ct. 1245). This relationship, and the notions of Indian sovereignty and self-government embodied in it, “provide[ ] an important ‘backdrop’ against which vague or ambiguous federal enactments must always be measured.” White Mountain Apache Tribe v. Bracker, 448 U.S. 136, 143, 100 S.Ct. 2578, 65 L.Ed.2d 665 (1980) (quoting McClanahan, 411 U.S. at 172, 93 S.Ct. 1257 (1973)). It is, moreover, “well established that treaties should be construed liberally in favor of the Indians, with ambiguous provisions interpreted to their benefit.” Oneida II, 470 U.S. at 247, 105 S.Ct. 1245 (citations omitted). Any finding that Congress has abrogated Indian treaty rights is inappropriate “[a]bsent explicit statutory language.” Oneida II, 470 U.S. at 247, 105 S.Ct. 1245 (citation and internal quotation marks omitted); cf. Or. Dep’t of Fish & Wildlife v. Klamath Indian Tribe, 473 U.S. 753, 774, 105 S.Ct. 3420, 87 L.Ed.2d 542 (1985). Congress’s intention in that regard, in other words, must be “clearly expressed.” Hagen, 510 U.S. at 423 & n. 1, 114 S.Ct. 958 (Blackmun J., dissenting). B. Disestablishment and Diminishment Generally The Supreme Court applied and elaborated these canons in considering issues of reservation disestablishment and diminishment most recently in the “surplus land act” cases. These cases dealt with land claims arising from the allotment era and specifically addressed whether certain un-allotted lands opened for settlement to non-Indians remained in Indian country. Solem v. Bartlett, 465 U.S. 463, 104 S.Ct. 1161, 79 L.Ed.2d 443 (1984), for example, involved a writ of habeas corpus sought by a non-Indian who had been tried and convicted in state court for a crime committed on a Sioux reservation. The question presented was whether the state had jurisdiction over the petitioner by virtue of the Cheyenne River Act, which had authorized the Interior Secretary to allot a portion of the reservation to homesteaders. In concluding that the reservation had not been diminished, the Court set forth the standard for identifying the “clear” expressions of congressional intent needed to find diminishment. It began by noting that only Congress can divest a reservation of its land and diminish its boundaries. Once a block of land is set aside for an Indian Reservation and no matter what happens to the title of individual plots within the area, the entire block retains its reservation status until Congress explicitly indicates otherwise .... Congress [must] clearly evince an intent to change boundaries. Id. at 470, 104 S.Ct. 1161 (emphasis added) (citations and internal quotation marks omitted). Although “[e]xplicit reference to cession or other language evidencing the present and total surrender of all tribal interests” can be helpfully probative, particularly when buttressed by fixed compensation for the opened lands, id., this language is not a prerequisite for a finding of diminishment. Rather, an act’s legislative history and the subsequent treatment of the land (including settlement patterns), may also suffice: When events surrounding the passage ... — particularly the manner in which the transaction was negotiated with the tribes involved and the tenor of legislative Reports presented to Congress— unequivocally reveal a widely held, contemporaneous understanding that the affected reservation would shrink as a result of the proposed legislation, we have been willing to infer that Congress shared the understanding that its action would diminish the reservation, notwithstanding the presence of statutory language that would otherwise suggest reservation boundaries remained unchanged. To a lesser extent, we have also looked to events that occurred after the passage of a surplus land Act to decipher Congress’ intentions. Congress’ own treatment of the affected areas, particularly in the years immediately following the opening, has some evidentiary value, as does the manner in which the Bureau of Indian Affairs and local judicial authorities dealt with unalloted open lands. On a more pragmatic level, we have recognized that who actually moved onto opened reservation lands is also relevant to deciding whether a surplus land Act diminished a reservation. Where non-Indian settlers flooded into the opened portion of a reservation and the area has long since lost its Indian character, we have acknowledged that de facto, if not de jure, diminishment may have occurred. In addition to the obvious practical advantages of acquiescing to de facto diminishment, we look to the subsequent demographic history of opened lands as one additional clue as to what Congress expected would happen once land on a particular reservation was opened to non-Indian settlers. Solem, 465 U.S. at 471-72, 104 S.Ct. 1161 (citations omitted); see also South Dakota v. Yankton Sioux Tribe, 522 U.S. 329, 344, 118 S.Ct. 789, 139 L.Ed.2d 773 (1998) (stating that the Court may consider “ ‘the historical context surrounding the passage of the surplus land Acts,’ and to a lesser extent, the subsequent treatment of the area in question and the pattern of settlement there” (quoting Hagen, 510 U.S. at 411, 114 S.Ct. 958)). But when these elements, considered in their totality, “fail to provide substantial and compelling evidence of a congressional intention to diminish Indian lands, we are bound by our traditional solicitude for the Indian tribes to rule that diminishment did not take place and that the old reservation boundaries survived the opening.” Solem, 465 U.S. at 472, 104 S.Ct. 1161. The same analysis applies to the termination or disestablishment of a reservation. See DeCoteau v. Dist. County Court for the Tenth Judicial Dist., 420 U.S. 425, 444, 95 S.Ct. 1082, 43 L.Ed.2d 300 (1975) (“[The Supreme Court] does not lightly conclude that an Indian reservation has been terminated .... ‘[T]he Court requires that the congressional determination to terminate ... be expressed on the face of the Act or be clear from the surrounding circumstances and legislative history.’ ”) (quoting Mattz v. Arnett, 412 U.S. 481, 505, 93 S.Ct. 2245, 37 L.Ed.2d 92 (1973)). Applying these principles, the Supreme Court has found language supporting diminishment in cases where the operative portion of a surplus land act reflects an Indian agreement to “cede, sell, relinquish and convey” opened lands. See, e.g., Yankton, 522 U.S. at 344, 118 S.Ct. 789; DeCoteau, 420 U.S. at 439, 441 n. 22, 95 S.Ct. 1082; Rosebud Sioux Tribe v. Kneip, 430 U.S. 584, 591 & n. 8, 97 S.Ct. 1361, 51 L.Ed.2d 660 (1977). Similarly, in Hagen v. Utah, the operative language provided that “all the unallotted lands within said reservation shall be restored to the public domain,” 510 U.S. at 412, 114 S.Ct. 958 (emphasis added), which the Court found indicated a congressional intent to diminish. Id. at 414, 114 S.Ct. 958. In each of these cases, the Supreme Court found a textually grounded intention to diminish supported by legislative history. To varying degrees the Court also found other support such as contemporaneous congressional and administrative statements, proclamations opening the reservation to settlement, the state’s assumption of jurisdiction over the opened lands, and the subsequent pattern of settlement. See Yankton, 522 U.S. at 351-57, 118 S.Ct. 789; Hagen, 510 U.S. at 416-21, 114 S.Ct. 958; DeCoteau, 420 U.S. at 437-49, 95 S.Ct. 1082; Rosebud, 430 U.S. at 592-615, 97 S.Ct. 1361. C. The Buffalo Creek Treaty As we have seen, Articles 1 and 2 of the Buffalo Creek Treaty summarize the central bargain between the New York Indians and the federal government: the cession of the New York Indians’ Wisconsin lands in exchange for reservation land in Kansas. Most of the remainder of the Treaty addresses the Kansas tract and various other tribe-specific arrangements. Articles 10 and 14 contain explicit cession language for the New York territory of two tribes, the Senecas and Tusearoras. Buffalo Creek Treaty, arts. 10, 14; see New York Indians II, 170 U.S. at 21, 18 S.Ct. 531 (stating that the Senecas’ and Tusearoras’ agreements “indicate[d] an intention on the part, both of the Government and the Indians, that they should take immediate possession of the tracts set apart for them in Kansas”). In contrast, Article 13, which addresses the Oneidas, contains no such language: The United States will pay [certain sums to certain Oneidas] ... for expenses incurred and services rendered in securing the Green Bay country, and the settlement of a portion thereof; and they hereby agree to remove to their new homes in the Indian territory, as soon as they can make satisfactory arrangements with the Governor of the State of New York for the purchase of their lands at Oneida. Buffalo Creek Treaty, art. 13 (emphases added). Nothing in its text provides “substantial and compelling” evidence of Congress’s intention to diminish or disestablish the Oneidas’ New York reservation. There is no specific cession language, and no fixed-sum payment for opened land in New York; rather there is only the possibility of a sale for “uncertain future proceeds.” DeCoteau, 420 U.S. at 448, 95 S.Ct. 1082 (describing arrangement in Mattz, 412 U.S. 481, 93 S.Ct. 2245, 37 L.Ed.2d 92). Article 13 at best is ambiguous about whether removal to Kansas was required. More properly, it reflects a simple agreement to agree. While the Oneidas agreed to remove, removal was conditioned on speculative future arrangements between the Indians and a third party, New York’s governor. See New York Indians II, 170 U.S. at 28, 18 S.Ct. 531 (“It ... appears, from the eleventh, twelfth, and thirteenth findings [of the Treaty], that the President never fixed any time for [the Indians’] removal, as was contemplated in the third article.”) This contingency is reflected by the comments of Ransom Gillet, a federal Indian commissioner who participated in the Treaty negotiations and whose declaration is appended to the final document. Gillet stated that, in obtaining the Oneidas’ consent to the treaty, he “most solemnly assure[d] them that the treaty does not and is not intended to compel the Oneidas to remove from their reservation in the State of New York .... The treaty gives them lands if they go to them and settle there but they need not go unless they wish to. When they wish to remove they can sell their lands to the Governor of the State of New York and then emigrate. But they will not be compelled to sell or remove.” Statement of Ransom H. Gillet at Oneida Castle, Aug. 9, 1838 (emphasis added); see also Report of the Committee of Indian Affairs, State of New York, Mar. 24, 1847, at 4 (transcribing statement by a federal Indian commissioner to the Six Nations that they were not obligated to remove west). As it turned out, the sales to New York State were never accomplished, and the planned removal never took place. Oneida IIIb, 194 F.Supp.2d at 142. Article 3 of the Treaty, moreover, contemplates that some tribes might not remove from their New York lands: [S]uch of the tribes of the New York Indians as do not accept and agree to remove to the country set apart for their new homes within five years, or such other time as the President may, from time to time, appoint, shall forfeit all interest in the lands so set apart, to the United States. Buffalo Creek Treaty, art. 3 (emphasis added); see New York Indians II, 170 U.S. at 28, 18 S.Ct. 531. Accordingly, the Treaty’s text contains neither an obligation to remove nor any indication of a congressional intention to disestablish the Oneidas’ New York reservation. Sherrill and the amici nonetheless observe that certain legislative and administrative documents, such as “representative” reports of the Commissioner of Bureau of Indian Affairs spanning the period 1890 to 1997 and a 1981 Senate Report preceding the passage of New York’s Indian jurisdictional statute, 25 U.S.C. § 233, demonstrate that the Oneidas no longer have a New York reservation. While congressional and administrative references to the reservation may bear some general relevance to congressional intent, see Yankton, 522 U.S. at 351, 118 S.Ct. 789, the references cited by Sherrill, the earliest of which was decided a half-century after the Treaty’s proclamation, indicate little if anything about Congress’s intent in 1838. Given the absence of anything in the Buffalo Creek Treaty’s text or legislative history supporting disestablishment, we conclude that these later documents do not “unequivocally reveal” the intention necessary to demonstrate disestablishment. Solem, 465 U.S. at 471, 104 S.Ct. 1161. Moreover, two enactments in the wake of the Buffalo Creek Treaty weigh against disestablishment. Under an 1842 treaty between the Oneidas and New York, certain Indians who had not migrated to Wisconsin sold a portion of their New York land (amounting to some 1100 acres) to the State. This treaty provided for the conveyance of certain lots to the State and other lots to non-removing Indians to be held as “common property.” Boylan, 265 F. at 168 (quoting Treaty of 1842, arts. 1, 6). We later described this purchase as “such portion of the reservation as represented the equitable share in the proportion to the number of Indians who migrated.” Id. at 167-68 (emphasis added). Finally, an 1843 enactment of the New York legislature, which sought to allow the Oneidas to hold their lands in severalty and (improperly) to alienate them by majority vote of the chiefs and head men of the tribe, makes explicit reference to “lands and property in the Oneida reservation.” Id. at 169 (emphasis added) (quoting Act Relative to the Oneida Indians, Laws of the State of New York, 66th Sess., 244-46, Ch. 185, Sec. 1 (Apr. 8, 1843)). Sherrill and New York State also suggest that federal Indian removal policy, reflected in the Buffalo Creek Treaty, itself requires a finding that Congress intended to disestablish the reservation. In particular, the State argues that the “removal policy’s goal of reducing conflicting state and tribal sovereignty could be accomplished only if Oneida sovereignty over the area from which the Nation was obligated to remove was terminated.” New York Br. at 13. But this argument ignores both the requirement that removal language be “clearly expressed,” as well as the text of the Removal Act, which permits the President to provide western lands to “such tribes or nations of Indians as may choose to exchange the lands where they now reside, and move there.” 4 Stat. 411 (emphasis added). The State’s argument