[1] In the 1788 Phelps and Gorham Purchase, the Haudenosaunee (Iroquois) had previously sold rights to their land between Seneca Lake and the Genesee River.

The Treaty of Big Tree signed away their rights to all their territory west of the Genesee River except 12 small tracts[2] of land for $100,000 and other considerations (roughly $5 billion in 2020 dollars, in relation to GDP[3]).

[4] The delegates for both parties met from August 20, 1797 until September 16, 1797 at the rustic cabin of James and William Wadsworth, early settlers and land agents in the area, in what is now Geneseo, New York.

[4] This treaty is substantial as it opened up the rest of the territory west of the Genesee River for settlement and established twelve reservations, perpetual annuities and hunting and fishing rights for the Seneca in Western New York.

[9] The Livingston County Historical Society Museum in Geneseo, New York, houses a restored section of the Big Tree, which is believed to be the last remaining remnant, other than several pieces of furniture created by a 19th-century woodworker.

[7] The following reservations were guaranteed by the treaty: one piece or parcel of the aforesaid tract, at Canawaugas [fetid waters,[10] now Avon, New York], of two square miles, to be laid out in such manner as to include the village extending in breadth one mile along the riverone other piece or parcel at Big Tree [Gen-nis'-he-yo, Beautiful Valley[10]], of two square miles, to be laid out in such manner as to include the village, extending in breadth along the river one mileone other piece or parcel of two square miles at Little Beard's Town [Do-oh-nun-da-gah-a, Where the Hill is Near[10]], extending one mile along the river, to be laid off in such manner as to include the villageone other tract of two square miles at Squawky Hill [De-yu-it-ga-oh Valley Begins To Widen,[10] Leicester, New York], to be laid off as follows, to wit: one square mile to be laid off along the river, in such manner as to include the village, the other directly west thereof and contiguo's thereto one other piece or parcel at Gardeau [Ga-da'-o, Bank in Front[10] Mount Morris, New York], beginning at the mouth of Steep Hill creek, thence due east until it strikes the old path, thence south until a due west line will intersect with certain steep rocks on the west side of Genesee river, then extending due west, due north and due east, until it strikes the first mentioned bound, enclosing as much land on the west side as on the east side of the river.

In October, 1798, Augustus Porter, acting on behalf of Joseph Ellicott and the Holland Land Company, conducted a survey of the area.