Rossie is a town in St. Lawrence County, New York, United States.

The Town of Rossie is located on the southwestern border of the county and is west of Gouverneur.

During the War of 1812, residents constructed a block house in the southern part of Rossie.

The iron industry was important to the early town economy, and the Rossie Furnace of 1815 was the first to be built in northern New York.

The Oswegatchie River, looping back, flows in two directions in the south of Rossie.

A very small southern bay of Black Lake is at the north end of Rossie.