At the top, the Whirlwind Loop shares a short section of trail with the Mustang Loop Most riders will enter the Whirlwind Loop from here.

At the bottom of the main Whirlwind Loop, a 0.2-mile spur connects Whirlwind to the 7-up trail. If you were to start your ride eastbound on 7-up from its top at the Bull Run trailhead, it's 3.1 miles to Whirlwind. 7-up also ties the bottom of Whirlwind to the downhill ends of the other Horsethief trails Wildcat and Hildalgo .

On the Entrada sandstone, the Whirlwind trail is marked with purple stripes. Where Whirlwind and Mustang share a common trail for around one-tenth mile, the trail has both yellow and purple markings.

The loop can be done in either direction. When riding counterclockwise, you'll pass the trail fork for the Wildcat trail about 0.1 mile downhill after you leave the combined Whirlwind/Mustang segment.

There are frequent views of the Monitor and Merrimac area to the northeast, and of the La Sal Mountains to the southeast. The trail is surrounded by a scrub forest of juniper and pinion pine, with occasional sage and bitterbrush.

I'd estimate the trail to be about 70% slickrock, alternating with hardpack dirt. There will be some up-and-down riding in both directions. The climbing rate is reasonably gentle, with 350 vertical feet of elevation change over each side of the loop.

The riding surface is similar to the Mustang Loop -- a solid intermediate-level ride. I don't recall any tricky spots. It's exactly one mile from Mustang to the bottom of the loop (and the 0.2-mile spur to 7-up ) by either side of the loop, so the rates of climb and overall difficulty are similar whether you go clockwise or counterclockwise.

By connecting to 7-up downhill, you can make other loop options. For example, you could head east to Hildalgo or (via the 7-up singletrack option) to Wildcat for a bigger loop ride.

My recommended ride for intermediates is the "Horsethief Tour." See the track file below. It does the Mustang Loop clockwise, hitting the campground trails then the Whirlwind Loop counterclockwise before hitting the Wildcat-Hildalgo lariat. This ride is 14 miles with around 2000 vertical feet of overall climbing. See the track file below.

Bottom Line:
Not a "destination ride" by itself, but a very nice add-on loop to the Mustang trail. Well-designed and fun to ride.

Getting there:  From I-70 and Crescent Junction, drive south on US-191 for 20 miles (about 9 miles north of the Colorado River if you're driving out from Moab) to Highway 313. Drive uphill 11 miles.
Horsethief West:  On your right at mile 11.8 from Highway 191, turn toward the campground. The mountain bike trailhead is before the campground on your left. Start southbound on Chisholm to reach the Mustang-area trails.
Highway 313 (Chisholm) Trailhead:  At mile 12.5, spot the trailhead kiosk on the left side of the road. Turn into parking. Pedal east (away from the highway) on Chisholm to intercept the Mustang Loop in 0.5 mile.
Gemini Bridges Road (Getaway) Trailhead:  For longer rides of the area trails. At mile 12.9, turn left at the Gemini Bridges sign. About 200 feet from the pavement, spot a small parking area on your left with the Getaway Trail just east of parking. Mustang forks away from Getaway 0.6 miles from the trailhead.
Bull Run Trailhead:  Drive 1.1 miles down the Gemini Bridges dirt road, then turn right into the trailhead. Start your ride to the Horsethief Area trails by heading left on 7up.