The Horse Valley Wilderness is part of the San Rafael Swell, which features magnificent badlands of brightly colored and wildly eroded sandstone formations, deep canyons, and giant plates of stone tilted upright through massive geologic upheaval. This landscape reveals a geological history laid bare through millennia of upheaval and erosion. The geologic history of the San Rafael Swell area began 40 to 60 million years ago when a massive uplift formed a geologic antic line. This bulge in the earth’s crust eventually eroded to leave high mesas, deep canyons, domes, spectacular arches, and spires. The terrain varies from the sheer cliffs and dazzling canyons to more gently carved badlands broken by shallow washes. The fins and folds of the San Rafael Reef jut through the southeast side of the area with dramatic sheer-walled cliffs, pinnacles, the knobs of Goblin Valley, twisted canyons, and valleys of stunning colors. Few canyons can compare to the entrenched, narrow gorges of the Black Boxes of the San Rafael River, which twists and turns through the San Rafael Swell. At the Head of Sinbad, water flows to the north, south, east, and west. Excavations have uncovered numerous fossils including more than 12,000 bones of at least 70 different animals as well as a dinosaur egg, complete with embryo.
Evidence of Native American cultures, including the Fremont, Paiute, and Ute, is common throughout the San Rafael Swell in the form of pictograph and petroglyph panels. From about 1776 to the mid-1850s the Old Spanish Trail trade route passed through (or just north of) the Swell.
The Swell provides excellent habitat for wildlife. More than 200 sure-footed Desert Bighorn Sheep live among the crags of this rugged landscape. Also found in the area are Bald Eagles and Peregrin Falcons, both Federally listed Endangered Species and other birds of prey, including Golden Eagles, Red-tailed Hawks, and Prairie Falcons.
Leave No Trace
How to follow the seven standard Leave No Trace principles differs in different parts of the country (desert vs. Rocky Mountains). Click on any of the principles listed below to learn more about how they apply in the Horse Valley Wilderness.
The San Rafael Swell is close to 1 million acres in size from Green River, UT west to highway 10 and Wayne County to the South. Cedar Mountain forms the northern boundary.
Digital and paper maps are critical tools for wilderness visitors. Online maps can help you plan and prepare for your visit ahead of time. You can also carry digital maps with you on your GPS unit or other handheld GPS device. Having a paper map with you in the backcountry, as well as solid orienteering skills, however, ensures that you can still route-find in the event that your electronic device fails.
Motorized equipment and equipment used for mechanical transport is generally prohibited in all wilderness areas.
This includes the use of motor vehicles, motorboats, motorized equipment, bicycles, hang gliders, wagons, carts, portage wheels, and the landing of aircraft including helicopters.