Near Medora in the northern half of Theodore Roosevelt National Park, the Achenbach and Buckhorn trails run through the 70,000 acre Theodore Roosevelt National Park. From its trailhead at the Squaw Creek Campground in the parks North Unit, the 16-mile Achenbach Trail fords the Little Missouri River a couple of times while snaking through the Achenbach Hills, a line of barren clay buttes dotted with juniper and sagebrush. Extend your hike via the Buckhorn Trail, an 11-mile loop that takes you through an active prairie dog town. Be ready for trecherous crossings of the Little Missouri River.
To reach the trailhead from Bismarck, take US 94 west 117 miles to the Belfield exit and then head north on US 85 for 50 miles to the North Unit entrance.
Overall, Achenbach/Buckhorn Trails is the 1st most popular hiking trail of all 7 hikes in North Dakota.