San Gorgonio Mountain, Mountain peak in San Bernardino National Forest, California, US

San Gorgonio Mountain is a summit in San Bernardino National Forest, California, rising to 11,503 feet (3,506 meters) above sea level. The mountain rises above terrain of pine forest and alpine meadows that transitions into rock scree and open ridgelines.

Spanish missionaries named the peak after Saint Gorgonius in the early 17th century. In 1952 a Douglas C-47 struck the eastern face at about 11,000 feet, killing all thirteen aboard; a Marine helicopter crashed during the recovery effort and its three crew survived. In 1977 a Learjet carrying Frank Sinatra's mother Dolly hit a ridge at 9,700 feet, killing all four on board.

Spanish missionaries in the early 17th century named the peak after Saint Gorgonius, a Christian martyr. Locals also call it Old Greyback, San Gor or San G, after the broad grey summit seen from a distance. The mountain lies in the San Gorgonio Wilderness, part of the Sand to Snow National Monument.

Hikers often start before sunrise to avoid afternoon thunderstorms in summer and to allow enough time for the return trip. The route passes through several climate zones, from conifer forest to treeless high country, so layered clothing helps.

On clear days the summit allows views of Mount Whitney located over 190 miles away. This line of sight ranks among the longest on the North American mainland.