Fairmont is a city in and the county seat of Martin County, Minnesota, United States. The population was 10,666 at the 2010 census.
Fairmont was platted in 1857. The city was so named on account of its elevated town site. A post office has been in operation at Fairmont since 1858. Fairmont was incorporated as a city in 1902.
According to the United States Census Bureau, the city has a total area of 16.92 square miles (43.82 km2), of which 15.04 square miles (38.95 km2) is land and 1.88 square miles (4.87 km2) is water. The city of Fairmont itself has been built around a chain of five lakes: Lake George, Sisseton Lake, Budd Lake, Hall Lake, and Amber Lake. All except Amber Lake are connected by channels and are used extensively for recreational boating and fishing. Interstate 90 and Minnesota State Highway 15 are two of the main routes in the city.
As of the census of 2010, there were 10,666 people, 4,812 households, and 2,816 families living in the city. The population density was 709.2 inhabitants per square mile (273.8/km2).