The Seneca maintain most of their administrative and public service facilities for the Cattaraugus Reservation in the Erie County portion.

According to the United States Census Bureau, the Indian reservation has a total area of 25.7 mi2 (66.5 km2 (25.7 sq mi) (65.6 km2) of it is land and 0.3 sq mi (0.78 km2) of it (1.36%) is water.

Cattaraugus Creek runs along the southern portion of the census division, and Lake Erie helps form the western boundary.

As of the census[5] of 2000, there were 2,001 people, 703 households, and 480 families living in the Indian reservation.

26.0% of all households were made up of individuals, and 11.0% had someone living alone who was 65 years of age or older.