Waseca is a city in Waseca County, Minnesota, United States. The population was 9,410 at the 2010 census. It is the county seat of Waseca County. U.S. Highway 14 and Minnesota Highway 13 are two of the main arterial routes in the city. According to the United States Census Bureau, the city has a total area of 4.9 square miles (12.8 km²), of which, 3.8 square miles (9.9 km²) of it is land and 1.1 square miles (2.9 km²) of it (22.42%) is water.