Arch Rock

Arch Rock is a natural stone arch tucked into a field of rounded boulders in Joshua Tree National Park. It is a great stop if you like getting close to the park's sculpted rock, though the arch is smaller than some people expect. The fun is finding its opening in the boulder maze and exploring the formations around it. Plan on about 1.4 miles for the full lollipop loop, 100 feet of climbing, and 45 to 90 minutes. The arch sits about a tenth of a mile into the rocky loop.

Start at Twin Tanks Parking Area. The path heads east on mostly sandy ground for about 0.6 mile, then makes a compact 0.2-mile rocky loop before returning along the same stem. Go counterclockwise around that loop; the arch is easier to pick out from that direction. The loop narrows to about one or two feet in places and gets rough underfoot. The route can be hard to follow among the boulders near the arch, so look for the path before scrambling around. This is not a wheelchair-accessible walk.

The trail has no shade, running water, or cell service. There is a vault or composting toilet at Twin Tanks, but no food service on the route, so bring what you need. Parking can be difficult on busy days, and groups sometimes wait their turn for photos; an early start helps with both. Summer heat can be dangerous, so if you go in summer, reach the trailhead before 10 a.m. Pets are not allowed on park trails; service animals are permitted on a six-foot leash.

Try framing the separate upright boulder through the arch; it gives the opening depth and makes a stronger picture than a tight shot of rock alone. The loop also shows Whale Rock, while Heart Rock is a short separate detour. The arch is a popular photo stop, so expect to share the rocks with other visitors at busy times.

The park's rounded monzogranite began as magma cooling underground more than 100 million years ago. As overlying rock wore away, fractures opened through the granite. Groundwater softened minerals along those cracks and rounded the blocks; later floods stripped away soil and exposed boulder piles across the desert. No source pins down when this particular arch formed, so that is the broader landscape story, not a date for Arch Rock itself.