THE SAN DIEGO COUNTY LAND BRIEF
Land in the
Diegan Western Granitic Foothills setting.
San Diego County has 4,210.9 square miles of land in California. 11 mapped landscape regions meet across San Diego County: Diegan Western Granitic Foothills, Southern California Lower Montane Shrub and Woodland, Diegan Coastal Hills and Valleys, among others.
Coastal and alluvial plains alternate with low hills in southern California. Sage scrub, chaparral and oak communities characterize the region's natural coastal landscape.
Regional context: Southern California/Northern Baja Coast ↗ · Regional mapping across the county footprint
Where the landscape changes
San Diego County intersects 11 mapped regional units. The largest mapped shares are:
- Diegan Western Granitic Foothills23.2%
- Southern California Lower Montane Shrub and Woodland15.7%
- Diegan Coastal Hills and Valleys14.5%
- Western Sonoran Basins10.9%
- Diegan Coastal Terraces10%
Southern California Mountains in San Diego County
Southern California's higher mountains support chaparral, oak woodland and conifer stands. Elevation and slope direction produce distinct vegetation patterns across these Mediterranean-climate ranges.
Read the regional source ↗Sonoran Basin and Range in San Diego County
Hot desert basins are separated by low mountain ranges. Palo verde, cacti and other drought-adapted plants distinguish the Sonoran setting from the Mojave region farther north.
Read the regional source ↗Finding your parcel within San Diego County
The atlas lists 57 cities, towns, townships, and Census communities associated with San Diego County, including San Diego, Chula Vista, Borrego Springs. The list includes overlapping geography types and does not divide the county into exclusive service areas.
San Diego County by land and water
The Census records 315 square miles of water within San Diego County, or 7% of its total area. That share is close to San Diego County’s 7%. This is geographic context; waterfront status and usable land must be checked at the parcel.
For scale, San Diego County has 250.9 times the land area of nearby San Diego Country Estates CDP (16.8 square miles). These areas describe boundaries, not comparable property prices.
The Census boundary meets Imperial County, Orange County, Riverside County within California. A tract near one of these lines should be matched to the county identifier on its own records.

