Mankato is a city in Blue Earth, Nicollet, and Le Sueur counties in the U.S. state of Minnesota. The population was 39,309 at the 2010 census, making it the fourth largest city in Minnesota outside of the Minneapolis-St. Paul metropolitan area. The county seat of Blue Earth County, it is located along a large bend of the Minnesota River at its confluence with the Blue Earth River. Mankato is across the Minnesota River from North Mankato. Mankato and North Mankato have a combined population of nearly 53,000. It completely encompasses the town of Skyline. North of Mankato Regional Airport, a tiny non-contiguous part of the city lies within Le Sueur County.Mankato is the larger of the two principal cities of the Mankato-North Mankato metropolitan area, which covers Blue Earth and Nicollet counties and had a combined population of 94,149 at the 2010 census. Mankato was designated a Metropolitan Statistical Area by the U.S. Census Bureau in November 2008.U.S. Routes 14 and 169 and Minnesota State Highways 22 and 60 are four of the main arterial routes in the city.