
The Niobrara River
The 'Niobrara River' is a tributary of the
Missouri River, approximately 430 mi (692 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.
It rises in the
High Plains of eastern Wyoming, in southern
Niobrara County, Wyoming. It flows east as an
intermittent stream past
Lusk and southeast into northwestern Nebraska. It flows southeast across the
Pine Ridge country of
Sioux County, then east through
Agate Fossil Beds National Monument, past
Marsland, and through
Box Butte Reservoir. It flows east across northern Nebraska, near the north edge of the
Sandhills, past
Valentine. It is joined by the
Snake River about 13 mi (21 km) southwest of Valentine. In north-central Nebraska it is joined by the
Keya Paha River approximately 6 mi (10 km) west of
Butte. It joins the Missouri northwest of
Niobrara in northern
Knox County.

Smith Falls is the tallest waterfall in Nebraska, and is located near the confluence of a prairie creek with the Niobrara River.
Two sections of the Niobrara River in central Nebraska have been designated as the
Niobrara National Scenic River.
The lower Niobrara valley is the traditional home of the
Ponca tribe of Native Americans.
Between 1861 and 1882, the stretch of the Niobrara River from the mouth of the Keya Paha its confluence with the Missouri marked the boundary between Nebraska and the
Dakota Territory.
See also
★
List of Nebraska rivers
★
List of Wyoming rivers