The singletrack trail climbs the west face of the Stansbury Island mountain to the top of the ridge. The trail is hard-packed but liberally coated with round quartzite boulders and chunks of limestone. The combination of steep grade (15%) and rocky trail will challenge your thighs. From here, we're looking west over the shallow west end of the Great Salt Lake.

The trail descends about 200 feet from the ridge, then hugs the shoulder of a horizontal band of conglomerate as it follows the canyons carved into the south face of the mountain. (The trail is just above the gray band in this picture.) The canyon walls are rocky and steep, with exposed cliff areas. Only advanced riders should tackle this ride -- novices may wind up as magpie bait.

Geologically, Stansbury Island is also an island of older rock sticking up through younger strata. As the Great Basin sank down, large blocks of rock pulled apart. The areas in between filled with sediments, leaving the "basin and range" topography of the Great Basin.

During the Silurian (440-410 million years ago) and Devonian (410-360 million years ago, "the age of fishes") periods, this was a near-shore area, where layers of dolomite ("limestone" that is high in magnesium carbonate, from times when the water was deeper) are separated by conglomerate (from times when rapid erosion deposited rock and debris along the shoreline at this location).

Outcrops of quartzite (highly compressed and heated rock formed from sand, indicating shoreline or near-shore deposits) from the Devonian Period are found on the southwest corner of the island

After following the shoulder where the limestone and dolomite meets the conglomerate layer around two canyons, the "official" trail descends back to the lake shore. (A trail continues on the shoulder area further around the island, but it becomes more technically difficult, and more dangerous. This is NOT a good place to be injured in early spring or late fall, as the weather can turn nasty quickly.) Following the road southwest to the "fork" (see below) then back northwest to the trailhead closes an 11-mile loop.

Getting there:
Take I-80 westbound out of Salt Lake. About 30 minutes later, you'll reach the second Grantsville exit (#84, UT-138, near the Morton salt plant). After exiting, proceed straight (onto the crummy road) rather than turning towards Grantsville. Follow the road north as it turns into gravel and crosses the mud flats, about three miles. At the fork, stay left. There should be a "Stansbury Island Mountain Bike Trail" sign at this fork. (Look around -- this is where the trail returns after you come off the mountain.) Two miles later, you'll come to a four-way intersection. There may, or may not, be a stop sign there. Go straight through. 1.1 miles later, you should see a "Bike Trail" sign and a road branching off on the right. Turn right and drive a few hundred yards to the parking area. There are no fees (and no facilities of any kind).