Little Bighorn River Canyon in Wyoming, the Little Bighorn receives other mountain streams as tributaries including the Dry Fork (which despite its name maintains a permanent, year-round significant flow of water into the Little Bighorn), and the West Fork of the Little Bighorn. After issuing from its canyon at the Montana-Wyoming line the Little Bighorn flows northward across the Crow Indian Reservation. The river flows past the towns of Wyola, Lodge Grass and Crow Agency, and joins the Bighorn River near the town of Hardin. At Wyola, Montana, the Little Bighorn receives the flow of Pass Creek flowing north from the Bighorn Mountains.
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