South Hills (California)

South Hills
View of the South Hills from the top of Colby Trail
Highest point
Elevation370[1] m (1,210 ft)
Geography
South Hills
location of South Hills in California[1]
CountryUnited States
StateCalifornia
DistrictLos Angeles County
Range coordinates34°7′16″N 117°50′50″W / 34.12111°N 117.84722°W / 34.12111; -117.84722
Topo mapUSGS San Dimas
BiomeChaparral and coastal sage scrub
Geology
Rock ageMiocene (approximately 15–17 million years ago)
Rock typeMiocene volcanic rocks (Glendora Volcanics)

The South Hills are a low mountain range of the Transverse Ranges in eastern Los Angeles County, California. Located within the San Gabriel Valley, they rise in the southern portion of the city of Glendora between the San Gabriel Mountains and the larger Los Angeles Basin. Much of the hills consist of volcanic rock formed about 15–17 million years ago, when eruptions in this area produced lava flows that later hardened into stone.[2][3] These rocks, known as the "Glendora Volcanics," form much of the hills today and help explain why they rise above the surrounding landscape. Their elevation ranges from 740 ft at the base to 1212 ft at their highest peak.[1][4]

The South Hills are north of the Interstate 210 Freeway, in the southern part of the city of Glendora, with the western portion of the hills in the City of Glendora's South Hills Park. They are north of the unincorporated town of Charter Oak and northwest of the city of San Dimas.

References

  1. ^ a b c "South Hills". Geographic Names Information System. United States Geological Survey, United States Department of the Interior. Retrieved 2009-05-04.
  2. ^ "Glendora volcanic rocks". U.S. Geological Survey, National Geologic Map Database. Retrieved 27 February 2026.
  3. ^ "Age and tectonic significance of volcanic rocks in the northern Los Angeles Basin, California" (PDF). U.S. Geological Survey. Retrieved 27 February 2026.
  4. ^ Swinney, Dick (1994). Glendora Foothills Plant Checklist San Gabriel Mountains. Sun Valley, California: Theodore Payne Foundation. p. 2. ISBN 0-9627781-1-7.