Achenbach/Bison Trail Loop is a 13.6 mile lightly trafficked loop trail located near Grassy Butte, North Dakota that features a river and is rated as difficult. The trail offers a number of activity options and is best used from March until November. Horses are also able to use this trail.

Distance: 13.6 miles Elevation Gain: 1,587 feet Route Type: Loop




horseback riding

nature trips





wild flowers



over grown

washed out

no dogs

The loop can be done several ways starting either out of Juniper campground beginning with 1 of 2 necessary river crossings and doing the extent south of the river first, or it can be done from the Caprock coulee trailhead heading west, doing the extant north of the river first. This trail circles a large portion of the west end of Theodore Roosevelt National Park North Unit. Can be done as a strenuous day hike or backcountry backpacking trip is suggested. Trail crosses the Little Missouri River twice and a majority is within the designated wilderness area of the park. It is best to pack all water due to high sediment content of LM River and unreliable spring flow. NOTE The trail does not come to a complete loop. 2 miles of hiking along the road, hitchhiking, or a 2nd dropped vehicle are required. Uphill and downhill gradient in both directions. Little Missouri River crossings are easiest in summer months due to low river conditions. Strenuous sections climb buttes and drop down into coulees. A large portion of the trail follows the sage brush flats and winds around the base of the buttes.

over grown
Fri Apr 19 2019

This is a good trail at 3.5 mile it got really muddy and I had to detour to find a more suitable path. After this trail leaves the achenbach there are no markers and one could wander aimlessly without a gps or trail app to reference. once the trail heads out of the flats it's a steep scramble on a bentonite trail. Good trail can be boring at times but the steep trail in and out of the flats is worth it. HAVE BUG REPELLENT!

Wed Jun 19 2013

hiked the north achenbach. the trailmarkers are hard to see and the trail follows animal paths. it is easy to follow a path off the trail so watch carefully for the markers. early summer ticks are terrible through the grasslands bring repellant and be prepared to reapply. in my opinion if hiking the north unit the caprock coulee loop is a much more enjoyable hike. the veiws are better and the hills a little tougher. it is marked much better as well.

Sun Apr 26 2015