Fargo is the most populous city in the U.S. state of North Dakota and the county seat of Cass County. The population was 125,990 at the 2020 census, which was estimated to have grown to 133,188 in 2023, making it the 218th-most populous city in the United States. Fargo, along with its twin city of Moorhead, Minnesota, form the core of the Fargo–Moorhead metropolitan statistical area, which had a population of 248,591 in 2020. Fargo was founded in 1871 on the Red River of the North floodplain.