Black River is a 4.2-mile-long (6.8 km) river in the southwest part of the U.S. state of Michigan that empties into Lake Michigan in South Haven at 42°24′08″N 86°17′04″W / 42.40222°N 86.28444°W, where it discharges past the South Pier Lighthouse. The river takes its name from the dark brown color of its water, which is caused by suspended sediments and organic materials picked up along its course. The river supports a variety of wildlife including trout, snapping turtles, leeches, and many other varieties of flora and fauna. The Black River watershed encompasses 287 square miles (740 km2) across two counties and 13 townships.