Towering above Interstate 5 and the headwaters of the Sacramento River, the granite spires of the Castle Crags are one of the most popular hiking goals of Northern California. For a quick bit of exercise walk to Indian Springs, where cold water spurts from a cliff. For a tougher hike, continue up to Castle Dome, an enormous granite monolith with a panoramic view of the Mt. Shasta area.

The Castle Crags’ granite domes look as though they rose straight up from the depths of the planet—and they did. For several hundred million years the North American continent has been crunching its way over the Pacific plate. In the process, the descending seafloor drags down a lot of sand and mud with it. When this relatively light sedimentary material gets deep enough it melts to form granite. Then it bubbles up through the continent toward the surface. Castle Dome, like Yosemite Valley’s Half Dome, is the rounded top of a granite bubble that cooled underground and was later exposed by erosion.

In the late 1920s, photographs of these picturesque crags were used in the campaign to create California’s state park system. Today the park includes a campground, several short nature trails, 7 miles of the Pacific Crest Trail, and a portion of the Castle Crags Wilderness. Dogs are not allowed on park trails.

Start by driving Interstate . . .

This chapter is an excerpt from 100 Hikes: Southern Oregon