What is the length of the River which has Wild Horse Creek as a tributary ?
Powder River (Wyoming and Montana) Powder River is a tributary of the Yellowstone River, approximately 375 mi long in northeastern Wyoming and southeastern Montana in the United States. It drains an area historically known as the Powder River Country on the high plains east of the Bighorn Mountains.
Blacktail Deer Creek Blacktail Deer Creek is a tributary of the Beaverhead River, approximately 38 mi long, in southwest Montana in the United States.