The Virgin River Gorge is located at about the mid-way point on the road trip from Las Vegas to Zion National Park, and represents the geographical transition between the Basin & Range and the Colorado Plateau. From the parched desert floor of the Mesquite Valley the road winds and climbs upward into brightly colored horizontal layers of sedimentary rock that tower just above the roadbed. It is literally a mini-Grand Canyon because it contains the equivalent geologic layers that are found in the more famous national park located due east of the gorge. Many travelers are struck by the obvious similarity and some even think it's a part of the Grand Canyon.
In the middle of the gorge, near the Cedar Pockets exit (#27), the road crosses the Grand Wash Fault, which forms the western boundary of the Colorado Plateau, and is dropping the rock layers downward to the west. You can readily see the tilt in these gray limestone beds as you enter the gorge, but will notice that after you cross the fault the layers become more uniformly flat lying and more brightly colored. The gray beds in the lower gorge are much older than the orange, red and tan layers of the upper part, which are related to those found in the Grand Canyon and are known as the Supai Group.
The lower gorge, cutting through the Pakoon Limestone layer.
This spectacular stretch of interstate highway was not completed until the early 1970’s and cost the then unheard of sum of one million dollars a mile to build. Prior to its construction travelers had to skirt the gorge to the west on old U.S. 91 and face a notoriously steep hill that was known to boil up the radiators of so many cars in the heat of summer that they built a service station in the shade of some rocks near the top of the pass.
The rim of the upper gorge is capped by Kaibab Limestone, looking north.
The first person to record a passage through the gorge was the legendary explorer and trapper Jedediah Smith who discovered that the Virgin River flowed into the Colorado and thus blazed the first overland trail to California from the desert interior in 1827. This later became known as the Old Spanish Trail and was used by traders traveling between Santa Fe and the small pueblos of Los Angeles and San Diego. These merchants traded highly prized California raised horses and mules for New Mexico blankets and textiles as well as Indian slaves. The slaves were usually Paiute women and children who were captured by mounted Utes and Navajos who'd try to sell them to Spanish and American caravans making their way through this stretch of country.
Today the trail parallels a scenic stretch of interstate that provides a vital link for commerce and travel connecting coastal California to the interior of the United States. It also hints to the traveler of the beautiful red rock scenery that is still yet to come.