The highway follows the southern bank of the Colorado River through a narrow, steep gorge, described as spectacular by National Geographic. The sheer sandstone walls of the gorge along Route 128 are recommended for their beauty on vacation guides from as far away as France and Germany.

The highway starts near Cisco. Cisco is a ghost town along the main line of the Denver and Rio Grande Western Railroad, founded as a water re-filling station for steam locomotives.The first 3 miles (4.8 km) of the road parallel the railroad and is an old routing of U.S. Route 6/U.S. Route 50, in use before the construction of I-70. After the Dewey Bridge (named for Dewey, a nearby ghost town) the road winds into the river gorge.

The gorge widens where the highway passes by Castle Valley and Professor Valley, which have been the shooting locations for many western films (including Wagon Master and Rio Grande) and television commercials. Sandstone rock formations towering over a valley Castleton Tower, spire visible from SR-128 that has been featured in several western movies and commercials.

Between Castle Valley and Moab, the Colorado River, and indirectly, Route 128, form the southern boundary of Arches National Park. Arches National Park is so named because of over 2000 natural arches inside park boundaries. While the highway does offer views of several features in the park, there is no park access along the highway.

As parts of the road are very narrow, with blind corners and no shoulders, the Utah Department of Transportation has prohibited trucks and vehicles over 55,000 pounds (24,948 kg) from the entire highway. In addition, a restriction at the junction with U.S. Route 191 requires vehicles over 15 feet (4.6 m) wide to have two police escorts.