The river system consists of a South Branch ( when including the Sexton-Kilfoil Drain) and a North Branch, which combine and run another to the Detroit River. Elevations run from above sea level in the northwest corner of the watershed to at the Detroit River. Over a year, it has a mean flow of per second. The Ecorse River has a watershed of . The north branch drains and has tributaries designated the Trouton Drain, Freeman Drain, Black Creek, and the Douglas and Kelly Drain. The south branch has a drainage area of , and tributaries include the Grams Drain in Southgate and the Brighton, Bondie, and the Sloss and Ganong Drains in Taylor. The rest of the watershed is drained by enclosed underground drains, the largest of which is the La Blanc Drain which enters the north branch about north of the junction of the north and south branches. The La Blanc Drain drains .