Wells County is a county located in the U.S. state of North Dakota. As of the 2010 census, the population was 4,207. Its county seat is Fessenden. The center of population of North Dakota is located in the extreme southeastern corner of Wells County, about 9 miles (14 km) southeast of Sykeston. As of the census of 2000, there were 5,102 people, 2,215 households, and 1,453 families residing in the county. The population density was 4 inhabitants per square mile (2/km2).