The San Ysidro Mountains are a mountain range in San Diego County

San Diego County, California

San Diego County is a large county located in the southwestern corner of the US state of California. Hence, San Diego County is also located in the southwestern corner of the 48 contiguous United States. Its county seat and largest city is San Diego. Its population was about 2,813,835 in the 2000...

, California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

. They are considered a part of the Peninsular Ranges

Peninsular Ranges

The Peninsular Ranges are a group of mountain ranges, in the Pacific Coast Ranges, which stretch from southern California in the United States to the southern tip of Mexico's Baja California peninsula; they are part of the North American Coast Ranges that run along the Pacific coast from Alaska...

. The range extends for a short distance into Baja California

Baja California

Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...

. The highest point of the range is Otay Mountain, elevation 3566 feet. The majority of the range is included in the Otay Mountain Wilderness Area. The vegetation is mostly coastal sage scrub

Coastal sage scrub

Coastal sage scrub is a low scrubland plant community found in the California chaparral and woodlands ecoregion of coastal California and northern Baja California. It is characterized by low-growing aromatic, and drought-deciduous shrubs adapted to the semi-arid Mediterranean climate of the...

 and chaparral

Chaparral

Chaparral is a shrubland or heathland plant community found primarily in the U.S. state of California and in the northern portion of the Baja California peninsula, Mexico...

. The range is one of the few places the rare Tecate Cypress is found. This tree was once abundant in the higher elevations of the range as well as in its canyons. However the range was totally deforested by wildfires in 2003 and 2007. However, there has been some evidence for Tecate Cypress regrowth.