Several Lolo National Forest campgrounds (www.fs.fed.us/r1/lolo [1]) are convenient to I-90. Cabin City Forest Service campground (Memorial Day–Labor Day, $7) is a little more than two miles off I-90 at exit 22, just east of De Borgia. Unless you hit a busy weekend, it’s relatively peaceful. The campsites are set in a lodgepole pine forest, and there’s a 0.75-mile nature hike down to Twelvemile Creek.
The Slowey (mid-May–late Sept., $10) campground is between exits 37 and 43. Quartz Flat (mid-May–late Sept., $10) is at the rest stop east of Superior, near mile marker 58. It’s convenient but exposed to I-90’s lights and noise.
Links:
[1] http://www.fs.fed.us/r1/lolo