“Visit this massive and magnificent dome of yellow sandstone, with streaks of red, pink, and white.
— Lee Watts
No wilderness permits are required. Cottonwood Canyon road becomes impassable after a rain. Carry plenty of water, because there is none to be found after you leave Cottonwood Creek.
The old horse trail that goes up this route is so eroded that this has essentially become a steep, off-trail adventure, which requires some scrabbling and route-finding skills. However, it is well-known and commonly traveled. A few cairns help indicate the right route.
The run starts from an unmarked parking area on Cottonwood Canyon Road, about 14 miles north of US 89. Yellow Rock cannot be seen from the road, so the easiest way to know where to start is to go to the Hackberry Canyon parking area, which does have a sign, and then drive back (south) 0.2 miles, just past a dirt road that heads off to the east.
The trail/route goes up a short, steep canyon directly across from the parking spot. To reach it, find a trail of use through the brush and cross Cottonwood Creek. Much of the year, the creek is a shallow stream that you have to wade across, but it is usually dry in the summer.
Shortly after you start up the canyon, you should see an eroded trail climbing steeply up a ravine to the right. The way up is not too difficult to follow, but try to remember exactly how you climb, because it is easier to take the wrong way when coming back down. When you reach a high point where you can see Yellow Rock, go a little to the left and then follow a very shallow canyon. Once you are on the rock, you can go anyway that you want. The south side has more colors and textures.
The broad, flat summit has sweeping views in all directions. There are other colorful rocks in the area, including a summit rock to the southwest that looks like a castle.