State Route 128 marker
State Route 128 marker

Utah 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 by the State of Utah. The highway also forms part of the Dinosaur Diamond Prehistoric Highway, a National Scenic Byway. The highway is commonly called the river road by residents of Moab, referring to the Colorado River, which the highway follows.

The highway was originally constructed by Grand County to connect rural cities in eastern Utah with Grand Junction, Colorado, the largest city in the region. The highway was partially absorbed into the state highway network in 1931, the rest was absorbed and assigned route number 128 in 1933.

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 the county conducting a study to determine the feasibility of reconstructing it.

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