Moreau River (South Dakota)

The Moreau River is a tributary of the Missouri River, approximately 200 miles (320 km) long, in South Dakota in the United States. Moreau River has the name of a pioneer trader.[4]

Moreau River Tributary to Missouri River
The Moreau River at Whitehorse
Location of Moreau River mouth Show map of South Dakota Moreau River (South Dakota) (the United States) Show map of the United States
Location
Country	United States
State	South Dakota
Counties	Dewey Edmunds Ziebach Perkins
Physical characteristics
Source	confluence of South and North Fork of Moreau River
• location	about 4 miles east-northeast of the intersection 156th Street and Zeona Road
• coordinates	45°08′41.96″N 102°49′50.60″W[1]
• elevation	2,490 ft (760 m)[1]
Mouth	Missouri River
• location	about 10 miles west of Akaska, South Dakota
• coordinates	45°22′29.96″N 102°24′48.49″W[1]
• elevation	1,614 ft (492 m)[1]
Length	290.75 mi (467.92 km)[2]
Basin size	5,435.32 square miles (14,077.4 km2)[3]
Discharge
• location	Missouri River
• average	337.63 cu ft/s (9.561 m3/s) at mouth with Missouri River[3]
Basin features
Progression	Missouri River → Mississippi River → Gulf of Mexico
River system	Missouri River
Tributaries
• left	North Fork Moreau River, Ash Creek, Mud Creek, Cottonwood Creek, Brady Creek, Cabin Creek, Starve Out Creek, Rabbit Creek, Mud Creek, Berry Creek, Locate Creek, Thunder Butte Creek, Sophia Creek, Irish Creek, Red Earth Creek, Meadow Creek, Redwater Creek, Little Moreau River, Whitehorse Creek, Jewett Creek, Jolley Creek, Handbou Creek, Marshall Creek, Du Charme Creek, Tom Hill Creek, Laundreaux Creek, Le Beau Creek, Chicken Creek
• right	Big Cabin Creek, Little Cedar Creek, Deep Creek, Badlands Creek, Flint Rock Creek, Knife Creek, Cottonwood Creek, Ash Creek, Pretty Creek, Bear Creek, Green Grass Creek, Gorge Creek, Cottonwood Creek, Bull Creek, Swan Creek, Johnson Creek, Blue Beaver Creek, Virian Creek, Beaver Creek, Hakshela Creek, No Mouth Creek
Bridges	Cedar Canyon Road, Bixby Road, SD 73, unnamed road, Thunder Butte Road, Leadum Pike Road, unnamed road (x4), SD 65, On the Tree Road, SD 63, unnamed road, BIA-3, The Native American Scenic Byway

The Moreau River, highlighted on a map of the Missouri River watershed

It rises in two forks in northwestern South Dakota, in the Badlands of Butte and Harding Counties. The North Fork rises approximately 10 miles (16 km) northeast of Crow Buttes. The South Fork rises approximately 20 miles (32 km) west of the headwaters of the North Fork. The two forks flow ESE and unite near Zeona in southern Perkins County. The combined stream flows east, past Usta, and across the Cheyenne River Indian Reservation, past Iron Lightning, Thunder Butte, Green Grass and Whitehorse. It joins the Missouri in Lake Oahe, with the lower 25 miles (40 km) of the river forming an arm of the reservoir.

The river generally parallels its neighbor 40 miles (64 km) to the north, the Grand River, running from west to east to join the Missouri. Draining the Pierre Hills and Northern Plateaus, the Moreau (formerly Owl River) has a drainage basin of approximately 5,400 square miles (14,000 km²). The Moreau River also has Sand Creek as a source, along with the North and South Forks, and claims several tributaries, such as the Little Moreau, Deep, Red Earth, Antelope, and Thunder Butte Rivers.[5] At Promise, the river averages a flow of 296 cubic feet per second (8.4 cubic metres per second).[6]