SNI meaning in Governmental ?

The Seneca Nation of Indians is a federally recognized Seneca tribe based in western New York. They are one of three federally recognized Seneca entities in the United States, the others being the Tonawanda Band of Seneca (also in western New York) and the Seneca-Cayuga Nation of Oklahoma. Some Seneca also live with other Iroquois peoples on the Six Nations of the Grand River in Ontario.

The Seneca Nation has three reservations, two of which are occupied: Cattaraugus Reservation, Allegany Indian Reservation, and the mostly unpopulated Oil Springs Reservation. It has two alternating capitals on the two occupied reservations: Irving at Cattaraugus Reservation, and Jimerson Town near Salamanca on the Allegany Reservation. A fourth territory de facto governed by the nation, the Cornplanter Tract in Pennsylvania, officially expired in 1957 and was submerged by the construction of the Allegheny Reservoir in 1965.