is a charter township of Wayne County in the U.S. state of Michigan. The population was 22,989 at the 2000 census. It is part of the collection of communities known as Downriver. Brownstown's three separate segments are due to the incorporation of the cities of Flat Rock, Rockwood, and Woodhaven in the early 1960s .
According to the United States Census Bureau, the township has a total area of 30.5 square miles (79.1 km²), of which, 22.5 square miles (58.1 km²) of it is land and 8.1 square miles (20.9 km²) of it (26.47%) is water. It is divided into three pieces, two of which meet at a corner.