In 2021, Cass County, MI had a population of 51.6k people with a median age of 45.4 and a median income of $60,725. Between 2020 and 2021 the population of Cass County, MI grew from 51,613 to 51,632, a 0.0368% increase and its median income grew from $57,514 to $60,725, a 5.58% increase.Web