The Prairie River is a small river that flows 54 miles (87 km)[2] through Branch and St. Joseph counties in Michigan.

The river rises at 41°48′20″N 85°00′54″W / 41.80556°N 85.01500°W / 41.80556; -85.01500 in northern Kinderhook Township in Branch County, and flows west-northwest into the St. Joseph River at 41°54′45″N 85°38′21″W / 41.91250°N 85.63917°W / 41.91250; -85.63917 just south of the city of Three Rivers, Michigan.

[3] The Prairie River drains all or portions of the following:[4] (from the mouth)[4]