Detroit River AOC is one of three binational AOCs. It drains an area of land in Michigan and Ontario that is approximately 700 square miles. Seventy-five percent of the AOC (607.7 square miles) is within Michigan boundaries (EPA 2008). The Detroit River itself runs a total of 32 miles as it progresses from Lake St. Clair to Lake Erie. 

It can be misleading to think of the Detroit River as a typical river with a fan-shaped watershed.  Instead, it is part of a strait that connects Lake Huron to Lake Erie, the Upper Great Lakes to the Lower Great Lakes. Lake Huron water comprises 95 percent of the flow of the Detroit River via the St. Clair River and Lake St. Clair (MDNR 1991).

There are five Michigan tributaries to the Detroit River:

1. The Rouge River 
2. Conners Creek
3. Monguagon Creek
4. Ecorse Creek
5. The Frank and Poet Drain

Three additional tributaries drain the Ontario portion of the watershed: 

1. Turkey Creek
2. Little River
3. Canard River

Lake St. Clair and two additional AOCs, the Clinton River AOC and the St. Clair River AOC, are immediately upstream of the Detroit River.

Every day, the river receives waste discharges from a wide variety of industrial and municipal sources.