Cassopolis is a village in the U.S. state of Michigan. As of the 2000 census, the village had a total population of 1,740. It is the county seat of Cass County6.
According to the United States Census Bureau, the village has a total area of 5.0 km2 (1.9 mi2). 4.5 km2 (1.8 mi2) of it is land and 0.5 km2 (0.2 mi2) of it is water. The total area is 9.33% water.