Wahpeton ) is a city in Richland County, North Dakota in the United States. It is the county seat of Richland County and had a population of 7,766 at the 2010 census. Wahpeton was founded in 1869 and is the principal city of the Wahpeton Micropolitan Statistical Area, which includes all of Richland County, North Dakota and Wilkin County, Minnesota.Wahpeton's twin city is Breckenridge, Minnesota. The Bois de Sioux River and the Otter Tail River join at Wahpeton and Breckenridge to form the Red River of the North.Wahpeton has two railroads, a bus line, five truck lines, and an airport with runways of just over 3,000 and 5000 ft in length.The North Dakota State College of Science is located in Wahpeton. The local newspaper is the Wahpeton Daily News.