The Milwaukee River Watershed makes up an area of 700 square miles located north of the Kinnickinnic and Menomonee Rivers. The Watershed covers portions of Dodge, Fond du Lac, Milwaukee, Ozaukee, Sheboygan, and Washington Counties. Since the Watershed is so large, and its branches are distinctly unique, the Milwaukee River Watershed is commonly thought of as four connected subwatersheds: the East and West Branch Subwatershed, the North Branch Subwatershed, the Cedar Creek Subwatershed, and the South Branch Subwatershed. Between these branches, the Milwaukee River flows over 476 stream miles, originating in springs and wetlands surrounded by rural forested and agricultural land use in its upper reaches, and eventually meeting Lake Michigan at the City of Milwaukee Harbor. Land cover throughout the Milwaukee River Watershed is approximately 18% urban/developed, 34% agricultural, 17% grassland, 14% forested/barren, and 16% wetland habitat. However, each subwatershed consists of distinctively different land coverage.
The Milwaukee River Watershed is also divided into four subwatersheds:
- North Branch Milwaukee River Subwatershed
- East & West Branch Milwaukee River Subwatershed
- Cedar Creek Subwatershed
- South Branch Milwaukee River Subwatershed