Arch Rock and Grand Tank reservoir | Joshua Tree National Park, CA

The Arch Rock Trail is a short walk inside the Joshua Tree National Park, in southeastern California. The boulders in the area are examples of monzogranite: molten liquid pushed from the earth’s core, cooled by the rocks closer to the surface. Centuries of wind and erosion has transformed the rocks into interesting shapes.

The path starts in the White Tank Campground near the Pinto Basin Road. It is a short, easy, and flat hike that takes you to the impressive 30-foot granite arch: the Arch Rock. The route has interpretive signs along the way detailing rock formations and geology.

The Arch is the most popular destination for visitors to White Tank. You can access the top and walk carefully through the arch.

Arch Rock

Past the arch, our path continues towards the Grand Tank reservoir. Small cement dams were added to natural rock dams to create seasonal water catchment during rainstorms. The added dam create a water supply for livestock over the hot summer months. We found the reservoir empty with dry sand, desert shrubs and with the water line clearly visible along the rocks.

Grand Tank