Seneca is a town in Ontario County, New York, United States.

The Town of Seneca is on the southern border of the county and is southwest of the City of Geneva.

The region was the locale of the Seneca tribe, a member of the Iroquois, and the sites of many important villages are in the town or the surrounding area; Kanadaseaga is one.

A "District of Seneca" was created judicially in 1789 at the time the county was established, but its extent and subdivisions are not clearly known.

The Levi Barden Cobblestone Farmhouse, Thomas Barron House, and Rippey Cobblestone Farmhouse are listed on the National Register of Historic Places.

[3] According to the United States Census Bureau, the town has a total area of 50.4 square miles (131 km2), all land.

15.4% of all households were made up of individuals, and 6.2% had someone living alone who was 65 years of age or older.