The Au Sable River in Michigan, United States runs approximately 138 miles (222 km) through the northern Lower Peninsula, through the towns of Grayling and Mio, and enters Lake Huron at Au Sable.

It is considered one of the best brown trout fisheries east of the Rockies and has been designated a blue ribbon trout stream by the Michigan Department of Natural Resources.

In French, au sable literally means “at the sand.”