Tent campers can head for one of the three Gallatin National Forest campgrounds (406/522-2520, www.fs.fed.us/r1/gallatin [1], mid-May–mid-Sept., $11) in Hyalite Canyon: Langhor is 11 miles south of town on Hyalite Canyon Road, and Hood Creek and Chisholm are another six and seven miles down the same road, respectively. Reach Hyalite Canyon Road by heading south on 19th Avenue.
Convenient though rather expensive camping is available at the Bozeman KOA (81123 Gallatin Rd., 406/587-3030 or 800/562-3036, tent $29, RV $44 and up, cabins $55), eight miles south of town on Highway 191, next door to Bozeman Hot Springs [2].
Links:
[1] http://www.fs.fed.us/r1/gallatin
[2] http://www.moon.com/destinations/montana/the-missouri-headwaters-and-south-central-montana/bozeman/recreation/bozeman-hot-springs