The Town of Rossie is located on the southwestern border of the county and is west of Gouverneur.
The first settler arrived around 1807.
The town was formed in 1813 from a section of the Town of Russell.
During the War of 1812, residents constructed a block house in the south 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. Lead mining was also important. The Rossie Shot Tower is still standing.