This trip begins by turning off I-90 at the Beulah Exit (#205). As you head south on the Sand Creek Road (C-129), you can see The Brakes to the north, Sugarloaf and Table Mountain to the northwest, and the Bear Lodge Mountains to the west. After one mile a side road (C-195) goes east to Shepherd Draw, but continue south below the rimrock and past some public fishing areas. The road travels through a canyon and past beautiful stands of boxelder, ponderosa pine, bur oak, and American elm trees. Further up the road are also hawthorn, paper birch, and aspen trees.
Five miles from the highway is the Ranch "A" Fish Hatchery and the Black Hills National Forest boundary and NF-863. For the next 17 miles you pass by several side roads (4WD) and gulches (Thompson, Idol, Manhattan, Surprise, Williams, and Plato). Several of these roads connect in South Dakota, where you can go to US-14A, south of Spearfish, but I have not traveled these routes. This entire route is just "plain pretty" and well worth the trip.
Twenty-three miles south of I-90, you come to a couple of junctions. At the first, you can turn northwest on the Moskee Road (NF-807) to I-90 exit #191 at Sundance. Stay south for a half mile to the next junction. At one time you could take the Moskee Road/Cold Creek Road south along Cold Creek but this road is closed to the public now.
Turn southeast on the Grand Canyon Road (NF-875). During the next few miles, you pass several side roads going to such places as Calvert Sacket Draw, Deer Lick, Schoolhouse Gulch, and Wagon Canyon. (Some of these roads also hit US-14A near Savory.)
Stay south on NF-875 and 10 miles south of the Moskee Road is O'Brian Springs. The road then begins to climb up the side of Bald Mountain. As you travel along the mountain, the road winds around and goes up and down for the next nine miles to the state line (where NF-875 changes to NF-175, the Willow Springs Road). You also pass by a few logging roads, but stay on the main road southeast and above some mountain meadows. Three miles from the state line, you hit US-85 in South Dakota (NF-106, Riflepit Road on this end), three miles from the state line.