Au Train Township is a township located in Alger County in the U.S. state of Michigan. As of the 2000 census, the township had a total population of 1,172.
According to the United States Census Bureau, the township has a total area of 428.6 km2 (165.5 mi2). 367.9 km2 (142.1 mi2) of it is land and 60.7 km2 (23.5 mi2) of it is water. The total area is 14.17% water.