Santa Rosa Region
The Santa Rosa Mountains in the northeast corner of Anza-Borrego Park rise 8,700 feet above the Borrego Valley desert floor, which lies between them and the San Ysidro Mountains to the southwest. The Santa Rosas were created by fault-block uplifting of the San Jacinto fault to comprise the northeastern arm of California's Penninsular Ranges Province.

This area is the most rugged and desolate region of the park, encompassing both 8,000-foot El Toro Peak and Palm Wash which lies below sea level. Lack of water and steep escarpments characterize this massive, jagged range.

Together with its sister range, the San Ysidros, the Santa Rosa prevented travel west from Los Angeles until quite recently. It wasn't until 1968 that a paved road (County Road S-22) was completed thorough the San Ysidros and across the Borrego Badlands.

The environment here is so extreme that, according to historical accounts, there were only three full-time residents of the Santa Rosa Mountains -- brothers Frank and Fred Clark and Cahuilla Indian Fig Tree John.

Because of the limited human influence in this region, a diverse plant community thrives here. Specialized plants like the Santa Rosa Sage, Parish's Larkspur and Elephant Trees flourish, as well as more common flora from Creosote shrubs to conifers.

This area is also home to more than half of the park's population of Bighorn Sheep, as well as the Western Mastiff Bat and the Pocketed Freetail Bat. Common reptiles and amphibians here include the Granite Night Lizard, the Desert Slender Salamander and the Red-spotted Toad.

No maintained or established trails or campgrounds exist in this area of the park. Backpackers are advised to register with park authorities before venturing here. Only skilled climbers attempt to climb Rabbit Peak. Car camping is allowed along any of the 15 miles of dirt roads in this sector accessible from County Road S-22 east of the town of Borrego Springs.