Either side of
Moab, the Colorado flows through spectacular red rock canyons, which are quite wide, allowing a paved road to follow close to the waters edge - Hwy 128 to the east and Hwy 279 (
Potash Road) to the west. In addition to
Arches National Park, there are many other interesting sites nearby, including narrower canyons, eroded formations, other arches, and ancient petroglyphs. Potash Road is much the quieter route, and extends for 15 miles, as far as an active mine; beyond here, the next approach of a road to the river is not for 60 miles (in a straight line) - at Hite, by the north end of Lake Powell.
Potash Road - full description