LaGrange Township is a civil township of Cass County in the U.S. state of Michigan. The population was 3,787 at the 2020 decennial census.
LaGrange Township is located just northwest of the center of Cass County. It is bordered by the city of Dowagiac to the northwest. The village of Cassopolis, the Cass County seat, is in the southeast part of the township. The unincorporated community of LaGrange is in the center of the township, at the west end of LaGrange Lake.
According to the United States Census Bureau, the township has a total area of 34.6 square miles (89.7 km2), of which 33.2 square miles (85.9 km2) is land and 1.5 square miles (3.8 km2), or 4.19%, is water.