Northfield is a city in Rice County, Minnesota, United States. A small portion lies in the adjacent Dakota County. The population was 20,790 at the 2020 census. Northfield is 40 mi (64 km) south of the downtowns of Minneapolis and St. Paul and is an exurb of the Minneapolis–St. Paul metropolitan area. It is home to two private liberal arts colleges, Carleton College and St. Olaf College.