Mankato is a city in Blue Earth, Nicollet, and Le Sueur counties in the U.S. state of Minnesota. It is the county seat of Blue Earth County. It is the 21st-largest city in Minnesota and fourth-largest outside of the Minneapolis–Saint Paul area with a population of 44,488 at the 2020 census, while the Mankato–North Mankato metropolitan area has an estimated 105,000 residents.