It rises in three forks in north central Wyoming. The North and Middle forks rise along the eastern slope of the Bighorn Mountains. The South Fork rises on the southern slopes of the Bighorn 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 (in the English language as well as in local indigenous languages) because the sand along a portion of its banks resembles powder or dust.