Madelia is a city in Watonwan County, Minnesota, United States, along the Watonwan River. The population was 2,308 at the 2010 census.
The city was named for the deceased daughter of Philander Hartshorn, a town founder. In 1876 the remaining members of the Younger gang were captured near Madelia after their failed attempt at bank robbery in Northfield, MN.
According to the United States Census Bureau, the city has a total area of 1.2 square miles (3.2 km²). None of it is covered by water.