The Missouri National Recreational River is a National Recreational River located on the border between Nebraska and South Dakota. The designation was first applied in 1978 to a 59-mile section of the Missouri River between Gavins Point Dam and Ponca State Park. In 1991, an additional 39-mile section between Fort Randall Dam and Niobrara, Nebraska, was added to the designation. These two stretches of the Missouri River are the only parts of the river between Montana and the mouth of the Missouri that remain undammed or unchannelized. The last 20 miles of the Niobrara River and 6 miles of Verdigre Creek were also added in 1991.

South Dakota is a landlocked state in the North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Dakota Sioux tribe, which comprises a large portion of the population with nine reservations currently in the state and has historically dominated the territory. South Dakota is the 17th largest by area, but the 5th least populous, and the 5th least densely populated of the 50 United States. Pierre is the state capital, and Sioux Falls, with a population of about 213,900, is South Dakota's most populous city. The state is bisected by the Missouri River, dividing South Dakota into two geographically and socially distinct halves, known to residents as "East River" and "West River". South Dakota is bordered by North Dakota to the north, Minnesota to the east, Iowa to the southeast, Nebraska to the south, Wyoming to the west, and Montana to the northwest.