Clarksville is a town located in Allegany County, New York, United States.

The town is in the southwest part of Allegany County, northeast of Olean.

[3] The west town line is the border of Cattaraugus County.

New York State Route 305 is an important north-south highway through the town.

20.8% of all households were made up of individuals, and 8.7% had someone living alone who was 65 years of age or older.