Le Sueur is a city in Le Sueur and Sibley counties in the U.S. state of Minnesota, between Mankato and the Twin Cities. It lies along the Minnesota River, just off U.S. Route 169. Le Sueur was named in honor of the French explorer Pierre-Charles Le Sueur. According to the United States Census Bureau, the city has a total area of 4.7 square miles (12.0 square kilometer), of which, 4.5 square miles (11.6 square kilometer) of it is land and 0.2 square miles (0.5 square kilometer) of it (4.09%) is water. A small part of the city extends into Sibley County.