The Au Sable River is formed by the confluence of the Kolke and Bradford Creeks just North of Frederic, Michigan. The river is approximately 130 miles long and runs generally West to East from Grayling, Michigan to Oscoda, Michigan on Lake Huron.

There are 3 primary branches to the Au Sable river.

The North Branch of the Au Sable which get's it's origions in Otsego County and flow south through Crawford County before joining the primary stream. The Middle Branch of the Au Sable flow south through Crawford County and Grayling and the South Branch of the Au Sable headwaters arise far south of the main brance near Roscommon, Michigan and flow west through the town of Roscommon and then north and east to merge with the Middle Branch. The main branch then flows easterly while passing through numerous dams and holding ponds.

Location