High Rock Canyon is one of nature’s masterpieces. It is a narrow defile cut 800 feet deep through layers of dark lava and multi-colored volcanic ash. The canyon can be traversed by high-clearance four-wheel-drive vehicles except between February 1st and the second week in May when the road is closed to protect wildlife during nesting and lambing times. Hiking is allowed year round. Vehicle camping is restricted to primitive, designated sites only. This is the best place in Black Rock-High Rock Country to view bighorn sheep and raptors.

The Applegate-Lassen Emigrant Trail passes through High Rock Canyon. Graffiti scratched into the rock walls or painted on with axle grease, known as emigrant glyphs, can still be seen here. These glyphs are important cultural resources graphically documenting a unique period in American history and are not to be damaged or embellished by adding modern graffiti.

Side canyons to High Rock include Little High Rock, Fly, Pole, Yellow Rock, and Upper High Rock, as well as the unusually formed Box Canyon. Each offer hiking or horseback adventures.

Between 10,000 and 14,000 years ago, two landslides blocked the drainage from intermittent High Rock Lake. The second slide caused Box Canyon to go dry and created a new lake outlet through Fly Canyon. Fly Canyon is best known today for its “potholes.” These potholes were carved in the bedrock of the canyon by sand and gravel swirled in whirlpools and can reach depths of several dozen feet. One large pothole is a dizzying 78 feet deep. Fly Canyon also contains the visible remnants of a difficult wagon slide traversed by the emigrants.

Mahogany Canyon is closed to motorized vehicles. It has perennial water where nature has reestablished a few trees in the wake of the emigrant migration and now offers hikers a cool, shady respite from the summer sun.

In Pole Canyon, remnants of homesteads begun in 1915 and abandoned before World War II can still be seen. Several of the homesteaders settled on lands that were already owned by a large ranching concern. This resulted in a four-year court battle that was eventually decided in favor of the large ranch.

Yellow Rock Canyon, named for yellowish-green rock composed of volcanic ash altered by plumes of hot water, shelters a stone garage built by homesteader David B. Fox shortly after 1915.

Stevens Camp is the remnants of an old buckaroo camp. There is an old line shack available to visitors on a first-come, first-serve basis. There are several information signs, a good horse corral, and a vault toilet, one of only a few in the NCA!

Upper High Rock Canyon is an extremely narrow, rocky section of the Applegate-Lassen Emigrant Trail that is closed to motorized vehicles. Because of the difficulty of travel there, the emigrants thought it was 10 miles long, but it is actually only one mile in length.

Little High Rock Canyon is considered to be the site of the last Indian massacre in the United States.

Massacre Ranch has a two-room cinder block cabin available on a first-come, first-serve basis. Legend has it that the area was named after a party of emigrants killed by Indians. No supporting information for this supposed massacre can be found. Obsidian, the black volcanic glass, is common in this area.