San Gorgonio Mountain, also known locally as Mount San Gorgonio, or Old Greyback, is the highest peak in Southern California and the Transverse Ranges at . It is in the San Bernardino Mountains, east of the city of San Bernardino and north-northeast of San Gorgonio Pass. It lies within the San Gorgonio Wilderness, part of the San Bernardino National Forest. Spanish missionaries in the area during the early 17th century named the peak after Saint Gorgonius.