Branch County is a county in the U.S. state of Michigan. As of the 2020 Census, the population was 44,862.[3] The county seat is Coldwater.[4] One of the "cabinet counties", it was named for John Branch, U.S. Secretary of the Navy under President Andrew Jackson.[1] The county was founded in 1829, and was organized in 1833. Branch County comprises the Coldwater, MI Micropolitan Statistical Area.