Montcalm County is a county in Michigan. As of the 2020 Census, the population was 66,614. The county is geographically located in the West Michigan region of the Lower Peninsula. The county seat is Stanton, and the largest city is Greenville. The county was set off in 1831 and organized in 1850.

According to the U.S. Census Bureau, the county has a total area of 721 square miles, of which 705 square miles is land and 15 square miles(2.1%) is water.