The San Diego Coast Peninsular Ranges include a series of ranges is separated by longitudinal valleys, trending NW-SE, subparallel to faults branching from the San Andreas Fault. The San Jacinto and Elsinore faults are especially significant topographically, defining precipitous escarpments along the margins of the principal mountain groups: including the San Jacinto Mountains, Santa Rosa Mountains, Santa Ana Mountains, Aqua Tibia Mountains, and the Laguna Mountains. The trend of topography is similar to the Coast Ranges, but the geology is more like the Sierra Nevada, with granitic rock intruding the older metamorphic rocks.

The region extends into lower California and is bound on the east by the Colorado Desert and on the north by the Los Angeles Basin and Transverse Ranges. The western boundary is defined by the Pacific Ocean, and it is characterized by a series of marine terraces that make overland travel relatively simple and provide locales suitable for agricultural and urban development. Its coastal margin was one of the earliest explored areas of the state, and it witnessed the founding of the state’s first Spanish outpost near San Diego Bay in 1769. Today San Diego is California’s second largest city.*

A collection of unique aerial panoramas of this region may be seen in the San Diego section of the California Atlas of Panoramic Aerial Images.