State Route 128 (SR-128) is a state highway in the U.S. state of Utah. The entire length of the highway has been designated the Upper Colorado River Scenic Byway, as part of the Utah Scenic Byways program. This road also forms part of the Dinosaur Diamond Prehistoric Highway, a National Scenic Byway. Residents of Moab frequently refer to SR-128 as "the river road", after the Colorado River, which the highway follows.

The highway was originally constructed to connect rural cities in eastern Utah with Grand Junction, Colorado, the largest city in the region. Today, the highway is used as a scenic drive for visitors to the area.

The highway crosses the Colorado River at the site of the Dewey Bridge, listed on the National Register of Historic Places. This bridge was the longest suspension bridge in Utah until April 2008 when it was destroyed by a fire started by a child playing with matches. The future of the bridge is uncertain, with Grand County conducting a study to determine the feasibility of reconstructing it.

State Route 128 begins just north of Moab, where it is commonly known as "the river road". 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.

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.

Between Moab and Castle Valley, 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.Popular attractions along this portion include Negro Bill Canyon, with hiking trails to Morning Glory Arch, campgrounds and boat docks at a curve in the river called Big Bend.

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. Near the east end of the valley the highway crosses Onion Creek, a stream sourced by springs that contain naturally occurring minerals that produce a strong odor in the water. At the east end of the valley the highway has a view of the Fisher Towers, a set of dark red spires.

en.wikipedia.org/wiki/Utah_State_Route_128