Mount Calavera's Vocanic 'Plug' - The History of Calavera Hills

The natural open space called Calavera is located in North San Diego County in the City of Carlsbad.  The area is bordered by the cities of Oceanside and Vista and lies approximately 2 miles from the Pacific Ocean.

The Word calavera means skull, which probably comes from the unusual shape of the area's centerpiece, Mount Calavera. The 513-ft Mount Calavera is not really a mountain at all but rather a 22 million-year-old- volcanic plug. A volcanic plug is a mass of volcanic rock that solidified in it's vent and feeding system millions of years ago. When the volcano becomes extinct and starts to erode away, the "plug" is all that is left behind.