To find the trailhead, take the forest road opposite the Cinnamon Lodge in Gallatin Canyon which is south of Big Sky and the Corral Restaurant and Bar. You drive just a short distance (maybe 1/2 mile) to the trailhead.
The trail follows Cinnamon Creek for 2.5 miles to a junction where it then goes up a ridge to the lookout. The trail if good in most places, but horses that have used the trail too early have trashed it up in the wet spots making it difficult to find a dry way through in a couple of places. You can have lunch just over the saddle at a spot with great views of the Taylor-Hilgard Basin. Worth the little side trip.
The trail continues through open meadows and aspen/pine timber to the top. The top is 9231 feet and there are spectacular views in all directions. A sign at the top indicates various distant peaks.
Head up early to avoid getting caught in the afternoon thunder storms. We got hail, rain and wind about 1/2 mile before the trailhead and the trail gets really slick once it starts raining. So, bring a raincoat and trekking poles--they will help keep you from sliding around in the mud.