FACT SHEET BOYDEN CAVERN IS NO LONGER OPERATED BY SIERRA NEVADA RECREATION. Email new lease owner, Stephen R. Fairchild. Boyden Cavern was discovered by surveyors in the late 1800s. After hearing stories about a large opening in the mountain, a logger named J.P. Boyden began to look for the cavern. When he found it he thoroughly explored it, and even did work to get it ready for public tours. Unfortunately, Boyden died of hypothermia while trying to hike out of the canyon in a blizzard before he was able to complete his plans. Sequoia National Forest included Boyden Cavern within its boundries on February 14, 1893. Boyden Cavern's main passageway is 1,000 feet long, 750 feet of which is open to the public. The remaining 250 feet require crawling to explore. While touring Boyden Cavern visitors see all types of amazing underground formations, including the somewhat rare "shield" formation. The spectacular Kings River Canyon, where Boyden Cavern is located, is the deepest canyon in the United States at 8,000 feet deep. Boyden Cavern lies beneath the massive 2,000-foot high marble walls of the famous Kings Gates. Boyden Cavern is actually only part of a five-mile-long cavern system, called Church Cave, that was formed over a period of 300,000 years. Nearby camping is available at Grant Grove, Indian Basin, Hume Lake, and Cedar Grove. Nearby sights include Grizzly Falls, Roaring River Falls, the famous Zumwalt Meadows, and the General Grant Tree which is also known as the "Nation's Christmas Tree." Boyden Cavern is open for tours from May through October.