Cottonwood Canyon Road (also known as Road 400) is a road located in Garfield County, Utah, United States. It has a length of 46 miles-76km (one way), it’s open all year (dry seasons), never suitable for RV’s or trailers and totally impassable when wet.
This gravel and sand scenic backway connects U.S. Highway 89 with Utah S.R 12 at Cannonville. It was originally constructed as a maintenance road for power lines following the canyon and runs for 46 miles traversing southward through Grand Staircase-Escalante National Monument. The road is paved for 9 miles between Cannonville and the turnoff to Kodachrome Basin State Park. Thereafter, the road is graded dirt with an underlying clay base making it impassable when wet. Inquire about weather and road conditions at the nearby Grand Staircase-Escalante National Monument Visitor Center in Cannonville to be prepared.
After rain, sections of road can become decidedly hazardous when fast-flowing creek crossings and slippery mud can cause road closures. It is considered impassable in wet weather. Many sections traverse ancient seabed deposits of mudstone, silt, and shale. When wet the clay surface becomes exceptionally slick, rendering even four wheel drive useless. Additionally many drainages cross the road in various locations, and these may wash out during periodic flash flooding, particularly during summer thunderstorms. Even in dry weather the road can be muddy to the point of being impassable in low areas.
Portions of the Cottonwood Canyon Road may be temporarily closed due to road work or inclement weather. During dry weather road 400 is a reasonably good quality dirt road (mostly sand and clay over a sandstone foundation). If the road has been recently graded it may be suitable for passenger cars, however high clearance vehicles are recommended.
If you dare to take the risk and travel along this dusty and bumpy route, then make sure to be driven by someone who has experience of the Cottonwood Canyon Road. There are no services available along the route except at Cannonville on the northern end. It is recommended to carry food, extra water and emergency supplies before traveling this road. This route should be avoided if significant rain or accumulating snow are in the forecast, and always check road conditions before setting out.