Au Sable, or Ausable, is a town in Clinton County, New York, United States. The population was 3,146 at the 2010 census. The name is from the Ausable River that flows through the town and means "at the sand".
The town is in the southeast corner of the county, south of Plattsburgh.
The land was first settled around 1795. The town was formed from part of the town of Peru in 1839. Mining was an important early industry in the town.
The AuSable Chasm Bridge was built in 1932-1933.