The Kalamazoo River is a river in the U.S. state of Michigan. The river is 130 miles long from the junction of its North and South branches to its mouth at Lake Michigan, with a total length extending to 178 miles when one includes the South Branch. The river's watershed drains an area of approximately 2,020 square miles and drains portions of ten counties in southwest Michigan: Allegan, Barry, Eaton, Van Buren, Kalamazoo, Calhoun, Jackson, Hillsdale, Kent and Ottawa. The river has a median flow of 1,863 cubic feet per second at New Richmond, upstream from its mouth at Saugatuck and Douglas.