THE SAN MATEO COUNTY LAND BRIEF
Land in the
Santa Cruz Mountains setting.
San Mateo County has 448.6 square miles of land in California. 6 mapped landscape regions meet across San Mateo County: Santa Cruz Mountains, San Mateo Coastal Hills, Leeward Hills, among others.
Pacific-facing coastal mountains support moisture-loving conifers, with marine terraces, dunes and beaches along the ocean edge. Inland slopes and the immediate coast have different vegetation patterns.
Regional context: Coast Range ↗ · Regional mapping across the county footprint
Where the landscape changes
San Mateo County intersects 6 mapped regional units. The largest mapped shares are:
- Santa Cruz Mountains41.7%
- San Mateo Coastal Hills24%
- Leeward Hills12.6%
- San Francisco Peninsula10.6%
- Bay Terraces/Lower Santa Clara Valley5.8%
Central California Foothills and Coastal Mountains in San Mateo County
Oak woodland, chaparral and grassland occupy foothills and low coastal mountains around the Central Valley. Narrow agricultural valleys interrupt this landscape of dry summers and wetter winters.
Read the regional source ↗Finding your parcel within San Mateo County
The atlas lists 33 cities, towns, townships, and Census communities associated with San Mateo County, including Redwood City, Pacifica, San Mateo. The list includes overlapping geography types and does not divide the county into exclusive service areas.
San Mateo County by land and water
The Census records 292.4 square miles of water within San Mateo County, or 39.5% of its total area. That share is close to San Mateo County’s 39.5%. This is geographic context; waterfront status and usable land must be checked at the parcel.
For scale, San Mateo County has 71.9 times the land area of nearby Half Moon Bay city (6.24 square miles). These areas describe boundaries, not comparable property prices.
The Census boundary meets Alameda County, San Francisco County, Santa Clara County, Santa Cruz County within California. A tract near one of these lines should be matched to the county identifier on its own records.

