Traveling about 10 miles (16 km) westbound on I-70 will lead to Fruita, a small town within view of the Colorado National Monument,[6] which features numerous scenic hiking trails.

From the trails, one may view attractions such as the Book Cliffs and Coke Ovens overlooks, and unique rock formations such as Independence Monument and the "Kissing Couple".

[7] Fruita is also the home of Mike the Headless Chicken, and hosts an annual festival in his honor every May.

[8] Just west of Fruita, the byway turns north onto SH-139, traveling 78 miles (126 km) to the next town of Rangely, and traversing the Douglas Pass.

[6] Continuing along the Dinosaur Diamond, US 40 and US 191 converge within Vernal, heading west for 30 miles (48 km) to the city of Roosevelt.

Nearby Duchesne are Fred Hayes State Park at Starvation[6] and Kings Peak (the highest point in Utah), which is part of the Uinta Mountain range.

[12] Within Duchesne, US 40 and US 191 diverge, and the DD continues 55 miles (89 km) south along US 191 over an unnamed mountain pass, through the small town of Helper, and into the larger city of Price.

The numerous attractions surrounding Price include College of Eastern Utah Prehistoric Museum,[13] Manti-La Sal National Forest, Huntington Lake State Park, Scofield State Park,[6] and Ninemile Canyon which features numerous petroglyphs.

[20] To be considered for designation "a road or highway must significantly meet at least one of the six scenic byways intrinsic qualities".

[24] The Utah State Road Commission took over US 40 from Kimball Junction to Colorado in 1910 and 1911,[25] and assigned the SR-6 designation to this route by the mid-1920s.

[26] In late 1926, the American Association of State Highway Officials (AASHO) assigned the designation of US 40 to this cross-state route, consisting of most of SR-4 and all of SR-6.

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

[30] 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.