Bighorn River river passes through Yellowtail Dam and Afterbay Dam. The river turns to the northeast and enters the Great Plains. At Hardin the river is joined by the Little Bighorn River. Approximately downriver from the Little Bighorn, in Big Horn County, the Bighorn empties into the Yellowstone. The Bighorn River has also been known as the Great Horn River, Le Corne and Iisaxpúatahcheeaashisee in the Apsáalooke language which translates to English as "Large Bighorn Sheep River". Bighorn River The Bighorn River is a tributary of the Yellowstone, approximately long, in the states of Wyoming and Montana in the western United States.
Little Bighorn River led a government expedition up the Big Horn River to the mouth of Big Horn Canyon, and then southeast along the base of the Big Horn mountains. En route to the Big Horn Canyon, and about 40 miles down the Big Horn River, he camped just below the mouth of the Little Bighorn on September 6, 1859. He noted in his journal for that day that the Indian name of the Big Horn river, into which the Little Bighorn empties, is "Ets-pot-agie", or Mountain Sheep River, and this generates the name of the Little Big Horn, "Ets-pot-agie-cate", or Little Mountain