About the Watershed
The North Branch Chicago River Watershed planning area covers 94 square miles (60,658 acres), with northern and southern boundaries roughly extending from Illinois Route 132 (Grand Avenue) in the City of Waukegan in Lake County south to Dempster Street in Morton Grove in Cook County. The watershed is made of up 25 municipalities, ten townships, four drainage districts and two wastewater treatment plants.
The North Branch Chicago River is formed from three tributary streams: the 17 mile Skokie River (or East Skokie), 24 mile Middle Fork (also known as the West Skokie), and the 14 mile West Fork.
From their origins in Lake County, these tributaries flow south into Cook County where they converge to form the main stem of the North Branch. The North Branch flows south through the Chicago River, South Branch, and Sanitary and Ship Canal to join with the Des Plaines River, which is a tributary of the Illinois and Mississippi Rivers.