Keeseville is a hamlet in Clinton and Essex counties, New York, United States. The population was 1,815 at the 2010 census. The hamlet was named after the Keese family, early settlers from Vermont. It developed along the Ausable River, which provided water power for mills and industrial development. Keeseville is in the towns of Au Sable and Chesterfield and is south of the city of Plattsburgh.