Powder River (Montana)
The EDZ Irigary Bridge over the Powder River
|- left||Crazy Woman Creek, Clear Creek, Mizpah Creek|
|- right||Wild Horse Creek, Little Powder River|
|Source||Confluence of Middle Fork and North Fork|
|- location||Near Kaycee, Wyoming|
|- elevation||4,564 ft (1,391 m)|
|- location||Near Terry, Montana|
|- elevation||2,241 ft (683 m)|
|Length||375 mi (604 km)|
|Basin||21,875 sq mi (56,656 km2)|
|Discharge||for Locate, MT|
|- average||558 cu ft/s (16 m3/s)|
|- max||31,000 cu ft/s (878 m3/s)|
|- min||0 cu ft/s (0 m3/s)|
Powder River (Assiniboine: Caȟní wakpá ) is a tributary of the Yellowstone River, approximately 375 miles (604 km) long in the southeastern Montana and northeastern Wyoming in the United States. It drains an area historically known as the Powder River Country on the high plains east of the Bighorn Mountains.
It rises in three forks in eastern Wyoming. The North and Middle forks rise along the eastern slope of the Bighorn Mountains. The South Fork rises on the north slope of Garfield Peak in the Granite Mountains west of Casper. The three forks meet on the foothills east of the Bighorns near the town of Kaycee. The combined stream flows northward, east of the Bighorns, and into Montana. It is joined by the Little Powder near the town of Broadus, and joins the Yellowstone approximately 50 miles (80 km) downriver from Miles City, Montana. The Powder River was so named because the sand along a portion of its banks resembled gunpowder.
Powder River has also been known as: Ce-than-i-ci-a, Chakadee Wakpa, Red Stone River, Redstone River, Wa ha Sah, Wah-har-sop, Wahasah, War-har-sa, and War-rak-sash.