The Temescal Mountains were originally named by the Spanish as Sierra Temescal (perhaps from the nearby
Rancho Temescal), a name which appears on the Rail Road Route survey map made by the
U. S. Army Pacific Railroad Surveys in 1854–55. The Temescal Mountains are one of the northernmost of
Peninsular Ranges of
California, running from the south side of the
Santa Anna River, southeast nearly parallel with the
Santa Ana Mountains, from which it is separated by the
Temescal Valley and
Elsinore Valley sections of the
Elsinore Trough. The Temescal Mountains were originally considered to be bounded on the south by the
San Jacinto River, by
J. D. Whitney in his 1865 Geological Survey of California. A later study by Rene Engel, considers the
Sedco Hills and the other mountains that extend to the southeast of the San Jacinto River east of Lake Elsinore and north of the Temecula Basin, in
Murrieta to be part of the same range forming the natural continuation of the mountains. The
Murrieta Hogbacks are the southeasternmost heights of the range, overlooking the
Warm Springs Creek Canyon. ==Geology==