Chief Joseph, Soda Butte, and Colter are Forest Service campgrounds (406/446-2103, www.fs.fed.us/r1/custer [1], July–mid-Sept., $8–9) just east of Cooke City [2] on the Beartooth Highway [3].
Links:
[1] http://www.fs.fed.us/r1/custer
[2] http://www.moon.com/destinations/montana/the-missouri-headwaters-and-south-central-montana/absaroka-beartooth-wilderness/cooke-city-and-silver-gate
[3] http://www.moon.com/destinations/montana/the-missouri-headwaters-and-south-central-montana/absaroka-beartooth-wilderness/beartooth-highway