Little Missouri River (North Dakota)
Encyclopedia
The Little Missouri River is a tributary of the Missouri River
, 560 mi (901 km) long, in the northern Great Plains
of the United States
. Rising in northeastern Wyoming
, in western Crook County about 15 miles (24.1 km) west of Devil's 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 (48.3 km) long called Little Missouri Bay and joins the main channel of the Missouri about 25 miles (40.2 km) northeast of Killdeer
.
The highly seasonal runoff from badlands and other treeless landscapes along the Little Missouri carries heavy loads of eroded sediment downstream. The sedimentary
layers, which extend from the headwaters in Wyoming all the way to the mouth in North Dakota, vary in age, but most of the beds along the river belong to the Bullion Creek and Sentinel Butte formations, both deposited during the Paleocene
(about 65.5 to 56 million years ago). The deposits include siltstone, claystone, sandstone, and lignite
coal laid down in a coastal plain during the Laramide orogeny
.
Missouri River
The Missouri River flows through the central United States, and is a tributary of the Mississippi River. It is the longest river in North America and drains the third largest area, though only the thirteenth largest by discharge. The Missouri's watershed encompasses most of the American Great...
, 560 mi (901 km) long, in the northern Great Plains
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. Rising in northeastern Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
, in western Crook County about 15 miles (24.1 km) west of Devil's Tower
Devils Tower National Monument
Devils Tower is an igneous intrusion or laccolith located in the Black Hills near Hulett and Sundance in Crook County, northeastern Wyoming, above the Belle Fourche River...
, it flows northeastward, across a corner of southeastern Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
, and into South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
. In South Dakota, it flows northward through the Badlands
Badlands
A badlands is a type of dry terrain where softer sedimentary rocks and clay-rich soils have been extensively eroded by wind and water. It can resemble malpaís, a terrain of volcanic rock. Canyons, ravines, gullies, hoodoos and other such geological forms are common in badlands. They are often...
into North Dakota
North Dakota
North Dakota is a state located in the Midwestern region of the United States of America, along the Canadian border. The state is bordered by Canada to the north, Minnesota to the east, South Dakota to the south and Montana to the west. North Dakota is the 19th-largest state by area in the U.S....
, crossing the Little Missouri National Grassland
Little Missouri National Grassland
Little Missouri National Grassland is a National Grassland located in western North Dakota, USA. At 1,033,271 acres , it is the largest grassland in the country. Enclaved within its borders is Theodore Roosevelt National Park, which is managed by the National Park Service...
and both units of Theodore Roosevelt National Park
Theodore Roosevelt National Park
Theodore Roosevelt National Park is a United States National Park comprising three geographically separated areas of badlands in western North Dakota. The park was named for U.S. President Theodore Roosevelt, in honor of his achievements in conservation as president and for the landscape's...
. In the north unit of the park, it turns eastward and flows into the Missouri in Dunn County
Dunn County, North Dakota
-Major highways:*North Dakota Highway 8*North Dakota Highway 22*North Dakota Highway 200-Demographics:As of the census of 2000, there were 3,600 people, 1,378 households, and 986 families residing in the county. The population density was 2 people per square mile . There were 1,965 housing units...
at Lake Sakakawea
Lake Sakakawea
Lake Sakakawea is a reservoir in the Missouri River basin in central North Dakota. Named for the Shoshone-Hidatsa woman Sakakawea, it is the third largest man-made lake in the United States, after Lake Mead and Lake Powell. The lake lies in parts of six counties in western North Dakota: Dunn,...
, where it forms an arm of the reservoir 30 miles (48.3 km) long called Little Missouri Bay and joins the main channel of the Missouri about 25 miles (40.2 km) northeast of Killdeer
Killdeer, North Dakota
As of the census of 2000, there were 713 people, 297 households, and 182 families residing in the city. The population density was 752.7 people per square mile . There were 351 housing units at an average density of 370.6 per square mile . The racial makeup of the city was 93.97% White, 4.91%...
.
The highly seasonal runoff from badlands and other treeless landscapes along the Little Missouri carries heavy loads of eroded sediment downstream. The sedimentary
Sedimentary rock
Sedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....
layers, which extend from the headwaters in Wyoming all the way to the mouth in North Dakota, vary in age, but most of the beds along the river belong to the Bullion Creek and Sentinel Butte formations, both deposited during the Paleocene
Paleocene
The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...
(about 65.5 to 56 million years ago). The deposits include siltstone, claystone, sandstone, and lignite
Lignite
Lignite, often referred to as brown coal, or Rosebud coal by Northern Pacific Railroad,is a soft brown fuel with characteristics that put it somewhere between coal and peat...
coal laid down in a coastal plain during the Laramide orogeny
Laramide orogeny
The Laramide orogeny was a period of mountain building in western North America, which started in the Late Cretaceous, 70 to 80 million years ago, and ended 35 to 55 million years ago. The exact duration and ages of beginning and end of the orogeny are in dispute, as is the cause. The Laramide...
.
See also
- List of North Dakota rivers
- List of longest rivers of the United States (by main stem)
- List of rivers of Montana
- List of South Dakota rivers
- List of Wyoming rivers
- Montana Stream Access LawMontana Stream Access LawThe Montana Stream Access Law says that anglers, floaters and other recreationists in Montana have full use of most natural waterways between the high water marks for fishing and floating, along with swimming and other river or stream-related activities...