This road also forms part of the Dinosaur Diamond Prehistoric Highway, a National Scenic Byway.

[4] The highway crosses the Colorado River at the site of the Dewey Bridge, listed on the National Register of Historic Places.

The highway follows the southern bank of the Colorado River through a narrow, steep gorge, described as spectacular by National Geographic.

[4] 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.

[8] Between Moab and Castle Valley, the Colorado River, and indirectly, SR-128, form the southern boundary of Arches National Park.

[12] 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.

[13] At the east end of the valley the highway has a view of the Fisher Towers, a set of dark red spires.

[10] 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.

[2] Access between Moab and Castle Valley was originally via a pack trail called the Heavenly Stairway.

[14] Isolated from Utah's population centers, this area depended on Grand Junction and other cities in Colorado for both everyday supplies and a market for agricultural products.

King was an early settler who also operated the toll ferry used prior to the construction of the Dewey Bridge.

Grand County held a municipal bond election, and was able to raise $25,000[16] (1913, approximately equivalent to $550,000 in 2008)[17] to finance the construction of a bridge.

[16] As part of a tribute, a reporter for The Daily Sentinel interviewed locals and visitors about their first experience crossing the bridge.

[16] An agreement was reached in 1984 between the Grand County Commission and the Utah Department of Transportation (UDOT) to balance the conflicting public demands to retire and preserve the aging bridge.

The east approach to the bridge features an abandoned gas station and the ghost town of Dewey.

[10] On April 6, 2008, a seven-year-old boy accidentally started a fire in a nearby campground while playing with matches.

The state legislature extended SR-128 about 3 miles (5 km) at its east end in 1969, due to the pending construction of Interstate 70.