Castle Crags is a dramatic granite formation in Northern California, shaped when a Jurassic granitic pluton was later exposed by Pleistocene glaciation and weathering into steep spires, pinnacles, and rounded domes. Along the ancient Siskiyou Trail, it stood within the ancestral homeland of the Okwanuchu Shasta and held sacred meaning for nearby Wintu, Achumawi, and Modoc communities. During the Gold Rush, miners driven by rumors of the Lost Cabin Mine invaded the area, leading to the 1855 Battle of Castle Crags. A mineral spring there was later commercialized through a bottling business and resort, and preservation efforts eventually helped create Castle Crags State Park.