View from the main spur off Ruby Ranch Road. You can park here and descend to go...
View from the main spur off Ruby Ranch Road. You can park here and descend to go directly to the sand dunes.
White Wash

White Wash is a motorcycle and ATV playground located about 15 miles southeast of Green River. There are some trails on the southwest corner of the region that may call out to you. There's free rock-roaming on Entrada sandstone in the area of the White Wash Sand Dunes. There's no marked trail on this rock -- your challenge is to find the spots that let you attack each ledge to conquer the next level of rock.

There are two ways into the sandstone, both of which involve some involvement with sand. From the north, you can follow the motorcycle singletrack Enduro Loop southbound down to White Wash, then jog into a side wash on Brian's Trail. There's wash-bottom riding in sand. So bring fat tires and thigh-to-spare, or be prepared to push your bike a bit.
The Entrada sandstone in the White Wash area offers slopes, ramps, and ridges. P...
The Entrada sandstone in the White Wash area offers slopes, ramps, and ridges. Part of the fun is finding the "solution" to getting up to the next level on the sandstone.
If you're looking for specific trails in this area, may I suggest:
   Dee Pass Loop (Intermediate)
   Red Butte and Slot (Advanced)
   Mary's Slickrock (Expert)
   Dead Cow Loop (Adventure)
The ride begins with a plunge from the bluff down to the flats of White Wash. It's only 500 vertical in 0.8 mile, but some areas are pretty steep. Whether you push your bike back uphill depends on how much the motorcycles have torn up the surface. You'll ride the clays of the late-Jurassic Morrison Formation down to the edge of the Entrada sandstone.
The Entrada playgrounds are found at the base of the cliffs. As as far as we could see, there's no way to ride this entire area continuously -- small washes penetrate slot canyons, turning the Entrada into sheer cliff.
View of the White Wash area
View of the White Wash area
Entry to Mary's Trail from the White Wash area.
Entry to Mary's Trail from the White Wash area.
The second entry into the area is via the main parking on the west side of the dunes. There are large parking corrals on the bluff along Ruby Ranch Road. After descending to White Wash, you'd need to hoof it northeast to reach the slickrock.
Trail notes (if ridden continuously) from the Enduro Trail:
0.0  Head south and plunge downward
0.9  Off the hill, heading S on ST
1.1  ST drops into wash
       Cross wash to R for Playground 1
       Down wash to continue ride
1.5  Small wash intersects White Wash
       N 38° 48.616' W 110° 01.126'
       Turn L (east)
1.8  Playground 2 on your L
       (Portage bike up onto rock)
2.1  Wash veers R (south)
White Wash
White Wash
Getting there, northern (Enduro) entry:  On I-70, drive 13 miles east of Green River. Get off at Floy Exit 175. Turn right and head south on Ruby Ranch Road. At mile 4.1 from I-70, keep right (left is Blue Hills Road). At around mile 7, keep left. Pass the barely-marked trailhead to Dee Pass at mile 7.2. When the road rises to the top of the mesa and turns slightly northward at mile 9.1, look for a flat open spot on your left. Look carefully for tire tracks crossing the road and heading south (to your left). GPS N 38° 49.572' W 110° 01.240'. This is the trailhead.

GPS track file (right-click and select "Save Target as..."):
     Multi-track GPX file of area

West (main Sand Dunes) entry:  As above, go southbound on Ruby Ranch Road. At mile 11.3, keep left at the fork. 
The first entry forks left at mile 11.8. After 0.1 mile, there's a broad parking area at the top of the bluffs. If your vehicle allows, you can descend another 0.2 miles to the edge of White Wash.
South entry:  For the south entry, stay straight (right) at mile 11.8. There will be parking on the left at mile 12.7 N38 47.705 W110 03.540.Veer left at mile 12.9. There will be four more parking spots along the road as it goes southbound, with the first right at N38 47.574 W110 03.681 and a final small spot on the edge of the bluff at N38 47.328 W110 03.788. The descending path to White Wash (and climb back out) is rough but (conditions permitting) can usually be done in a high-clearance SUV. Not that I recommend it.