Brown County is a county in the U.S. state of Minnesota. As of the 2020 census, the population was 25,912. Its county seat is New Ulm. The county was formed in 1855 and organized in 1856. Brown County comprises the New Ulm, MN Micropolitan Statistical Area and is included in the Mankato-New Ulm-North Mankato, MN Combined Statistical Ar…Brown County is a county in the U.S. state of Minnesota. As of the 2020 census, the population was 25,912. Its county seat is New Ulm. The county was formed in 1855 and organized in 1856. Brown County comprises the New Ulm, MN Micropolitan Statistical Area and is included in the Mankato-New Ulm-North Mankato, MN Combined Statistical Area.