Au Sable Forks is a hamlet in Clinton County and Essex County, New York, United States. The northern half of the community, within Clinton County, is listed as the Au Sable Forks census-designated place (CDP) and had a population of 559 at the 2010 census.

Clinton County is a county in the north-easternmost corner of the state of New York, in the United States and bordered by the Canadian province of Quebec. It is the northeastern most county in New York. As of the 2020 United States Census, the population was 79,843. Its county seat is the city of Plattsburgh. The county lies just south of the border with the Canadian province of Quebec and to the west of the State of Vermont. The county is named for George Clinton, the first Governor of New York, who later was elected as Vice President. He had been a Founding Father who represented New York in the Continental Congress. Clinton County comprises the Plattsburgh, New York Micropolitan statistical area. The county is part of the North Country region of the state.