Brownville is a town in Jefferson County, New York, United States.

The town is named after Jacob Brown, an early settler and leader.

Brownville is located in the western part of the county, northwest of Watertown.

Its name is derived from the founder and first settler, Jacob Brown, who was a major-general in the United States Army and is considered to be a heroic figure in the War of 1812.

Many of the northern towns of the county were established, or partly established, from parts of Brownville, including Le Ray (1806), Lyme (1818), Pamelia (1819), Orleans (1821), and Alexandria (1821).

New York State Route 12 crosses the northeastern corner of the town.

20.5% of all households were made up of individuals, and 9.1% had someone living alone who was 65 years of age or older.