The Missouri River is the longest river in North America. Rising in the Rocky Mountains of the Eastern Centennial Mountains of Southwestern Montana, the Missouri flows east and south for 2,341 miles (3,767 km) before entering the Mississippi River north of St. Louis, Missouri. The river drains a sparsely populated, semi-arid watershed of more than 500,000 square miles (1,300,000 km2), which includes parts of ten U.S. states and two Canadian provinces. Although nominally considered a tributary of the Mississippi, the Missouri River above the confluence is much longer and carries a comparable volume of water. When combined with the lower Mississippi River, it forms the world's fourth longest river system.
McKenzie County is a county in the U.S. state of North Dakota. As of the 2020 United States Census, the population was 14,704. Its county seat is Watford City.
Lake Agassiz was a large glacial lake in central North America. Fed by glacial meltwater at the end of the last glacial period, its area was larger than all of the modern Great Lakes combined, although its mean depth was not as great as that of many major lakes today.
The Red River is a river in the north-central United States and central Canada. Originating at the confluence of the Bois de Sioux and Otter Tail rivers between the U.S. states of Minnesota and North Dakota, it flows northward through the Red River Valley, forming most of the border of Minnesota and North Dakota and continuing into Manitoba. It empties into Lake Winnipeg, whose waters join the Nelson River and ultimately flow into Hudson Bay.
The Little Missouri River is a tributary of the Missouri River, 560 miles (901 km) long, in the northern Great Plains of the United States. Rising in northeastern Wyoming, in western Crook County about 15 miles (24 km) west of Devils Tower, it flows northeastward, across a corner of southeastern Montana, and into South Dakota. In South Dakota, it flows northward through the Badlands into North Dakota, crossing the Little Missouri National Grassland and both units of Theodore Roosevelt National Park. In the north unit of the park, it turns eastward and flows into the Missouri in Dunn County at Lake Sakakawea, where it forms an arm of the reservoir 30 miles (48 km) long called Little Missouri Bay and joins the main channel of the Missouri about 25 miles (40 km) northeast of Killdeer.
The Belle Fourche River is a tributary of the Cheyenne River, approximately 290 miles (470 km) long, in the U.S. states of Wyoming and South Dakota. It is part of the Mississippi River watershed via the Cheyenne and Missouri rivers. In the latter part of the 19th century, the Belle Fourche River was known as the North Fork of the Cheyenne River. Belle Fourche is a name derived from French meaning "beautiful fork".
The Cheyenne River, also written Chyone, referring to the Cheyenne people who once lived there, is a tributary of the Missouri River in the U.S. states of Wyoming and South Dakota. It is approximately 295 miles (475 km) long and drains an area of 24,240 square miles (62,800 km2). About 60% of the drainage basin is in South Dakota and almost all of the remainder is in Wyoming.
The White River is a Missouri River tributary that flows 580 miles (930 km) through the U.S. states of Nebraska and South Dakota. The name stems from the water's white-gray color, a function of eroded sand, clay, and volcanic ash carried by the river from its source near the Badlands. Draining a basin of about 10,200 square miles (26,000 km2), about 8,500 square miles (22,000 km2) of which is in South Dakota, the stream flows through a region of sparsely populated hills, plateaus, and badlands.
The Niobrara River is a tributary of the Missouri River, approximately 568 miles (914 km) long, running through the U.S. states of Wyoming and Nebraska. The river drains one of the most arid sections of the Great Plains, and has a low flow for a river of its length. The Niobrara's watershed includes the northern tier of Nebraska Sandhills, a small south-central section of South Dakota, as well as a small area of eastern Wyoming.
The Keya Paha River is a river flowing 127 miles (204 km) through the U.S. states of South Dakota and Nebraska.
The Cannon River a tributary of the Mississippi River flows 112 miles (180 km) from Shields Lake near Shieldsville to Red Wing in the U.S. state of Minnesota, where it joins the Mississippi River. It drains a watershed approximately 1460 square miles (3,780 km²) in size. The river flows through the counties of Le Sueur, Rice, Dakota, and Goodhue.
The James River is a tributary of the Missouri River, approximately 710 miles (1,140 km) long, draining an area of 20,653 square miles (53,490 km2) in the U.S. states of North Dakota and South Dakota. About 70 percent of the drainage area is in South Dakota. The river provides the main drainage of the flat lowland area of the Dakotas between the two plateau regions known as the Missouri Coteau and the Coteau des Prairies. This narrow area was formed by the James lobe of the Laurentide Ice Sheet during the last ice age, and as a consequence the watershed of the river is slender and it has few major tributaries for a river of its length.
The Missouri Coteau, or Missouri Plateau, is a large plateau that stretches along the eastern side of the valley of the Missouri River in central North Dakota and north-central South Dakota in the United States. In the Canadian provinces of Saskatchewan and Alberta this physiographic region is classified as the Uplands Missouri Coteau, which is a part of the Great Plains Province or Alberta Plateau Region, which extends across the southwest corner of the province of Saskatchewan as well as the southeast corner of the province of Alberta. Historically, in Canada the area was known as the Palliser's Triangle and regarded as an extension of the Great American Desert and unsuitable for agriculture and thus designated by Canadian geographer and explorer John Palliser. The terrain of the Missouri Coteau features low hummocky, undulating, rolling hills, potholes, and grasslands. Apart from being a geographical area, the Missouri Coteau also has a cultural connection to the people of the area, the Métis people of South Dakota, along with other Indigenous groups. The history of this plateau is large, and the Missouri Coteau has a significance to these people.
The Lac qui Parle River is a tributary of the Minnesota River, 118 miles (190 km) long, in southwestern Minnesota in the United States. A number of tributaries of the river, including its largest, the West Branch Lac qui Parle River, also flow in eastern South Dakota. Via the Minnesota River, the Lac qui Parle River is part of the watershed of the Mississippi River, draining an area of 1,156 square miles (2,990 km2) in an agricultural region. Slightly more than two-thirds of the Lac qui Parle watershed is in Minnesota. Lac qui parle means "lake which speaks" in the French language, and was a translation of the Sioux name for Lac qui Parle, a lake on the Minnesota River upstream of the mouth of the Lac qui Parle River.
The Dissected Till Plains are physiographic sections of the Central Lowlands province, which in turn is part of the Interior Plains physiographic division of the United States, located in southern and western Iowa, northeastern Kansas, the southwestern corner of Minnesota, northern Missouri, eastern Nebraska, and southeastern South Dakota.
The Drift Prairie is a geographic region of North Dakota and South Dakota.
Interstate 94 (I-94) runs east–west through the central portion of the US state of North Dakota.
South Dakota is a state located in the north-central United States. It is usually considered to be in the Midwestern region of the country. The state can generally be divided into three geographic regions: eastern South Dakota, western South Dakota, and the Black Hills. Eastern South Dakota is lower in elevation and higher in precipitation than the western part of the state, and the Black Hills are a low, isolated mountain group in the southwestern corner of the state. Smaller sub-regions in the state include the Coteau des Prairies, Missouri Coteau, James River Valley, the Dissected Till Plains. Geologic formations in South Dakota range in age from two billion-year-old Precambrian granite in the Black Hills to glacial till deposited over the last few million years. South Dakota is the 17th-largest state in the country.
The Missouri River Valley outlines the journey of the Missouri River from its headwaters where the Madison, Jefferson and Gallatin Rivers flow together in Montana to its confluence with the Mississippi River in the State of Missouri. At 2,300 miles (3,700 km) long the valley drains one-sixth of the United States, and is the longest river valley on the North American continent. The valley in the Missouri River basin includes river bottoms and floodplains.
Before the Pleistocene Ice Age, circa two million years before present (YBP), the rivers in North, South Dakota and eastern Montana drained northeast into Canada and then into Hudson Bay. The Keewatin Lobe of the continental ice sheet, block the flow of water northward and impounded it along the ice front. Lakes formed, until the waters could find a new way to drain. Initially, the north flowing rivers followed the front of the glacier eastward and into a valley that passed between Garrison and Riverdale, to the Turtle Lake area, and on into Sheridan County. This is known as the preglacial McClean River. This valley became blocked by the glacier and the glacial lake identified as Lake McKenzie formed. Eventually, water level rose to crest the south ridge a point near Riverdale — at the site of the modern Garrison Dam and a diversion trench was cut. The modern Missouri River follows this pathway.
