Mary Mountain Trail is a 40.5 mile lightly trafficked out and back trail located near Yellowstone National Park, WY that features a lake and is rated as difficult. The trail offers a number of activity options and is accessible from July until September.
Directions from Canyon Junction: Travel 4 miles south and north of Alum Creek to the pullout.
We did about 5mi of this trail from the Hayden Valley trail head. The trail is fairly flat and can get muddy if there has been rain. You can see lots of birds, hawks, and buffalo. You also get some nice views of distant geyser basins.
We did this as a day hike (start early). The scenery was simple in a beautiful way. Lots of large open meadows and some rolling hills as well as many bison eating off in the distance. We took a quick dip at the lake because it was hot. Was definitely worth hiking!!!
Because of all the tourist and traffic we desiderata at the last minute to do the trail. What a great choice We only went in several miles but we did not see one other hiker. Trail follows a perfect beautiful stream We felt like we were in another time. Great wildlife. We stumble across some awesome geysers that gave us our own viewing show. There was evidence of recent landslides and we spent time studying that. There are dangerous areas on the trail. When you see the white calcified ground be carful where you step. The ground is hollow and boiling water lurks just below so don't fall in you will die.
This was a most peaceful hike we loved it
Very confusing trail because of the bison that have trampled the trail and caused us to take one of their paths instead of the actual trail. Besides that a very moderate very scenic hike through Hayden Valley. Be careful of backcountry mud pots!!!