Mankato is a city in Blue Earth, Nicollet, and Le Sueur counties in the U.S. state of Minnesota. The population was 32,427 at the 2000 census. In 2008, the estimated population was 36,245 making it the fourth largest city outside of the Minneapolis-St. Paul metropolitan area. It is the county seat of Blue Earth County, and is located along a large bend of the Minnesota River at its confluence with the Blue Earth River. Mankato is located in Blue Earth County and neighbored by its sister city across the Minnesota River, North Mankato, and completely encompasses the town of Skyline. North of Mankato Regional Airport, a tiny non-contiguous part of the city also 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 85,712 at the 2000 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.