This is most often done as a simple out-and-back up South Cottonwood Canyon. The first 2.5 miles is suitable for novices (although the first pitch out of the parking lot will stress the unfit). The next 3.5 miles throws a few more challenges at you. After that, there's some loop options that require huge lungs and huge commitment. The Bozeman Area map from Big Sky Pulbishing shows this area very well.
Head South out of Bozeman on 19th Avenue. It will curve left and run into a tee. Go left (south again) at the T and follow the road around some tight curves, looking for a sign to the South Cottonwood trail. Turn left at the sign and follow the road to the trailhead.
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