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 and U.S. Highway 169. Le Sueur was named in honor of the French explorer Pierre-Charles Le Sueur. The population was 4,058 at the 2010 census.The community is known locally as the "Valley of the Jolly Green Giant".