Brunson is a city in Branch County in the U.S. state of Michigan. The population was 2,307 at the 2020 census. Incorporated as a city in 1…Brunson is a city in Branch County in the U.S. state of Michigan. The population was 2,307 at the 2020 census. Incorporated as a city in 1934, Brunson is mostly surrounded by Bronson Township, but the two are administered autonomously.