San Mateo County, California Zip Codes
📍 San Mateo County has 57 zip codes with a population of 724,829.
San Mateo County is located in California with a land area of 429 square miles. The county seat is San Mateo. Below you'll find all 57 zip codes in San Mateo County with population, income and home value, the county's affordability profile, and links to its 22 city pages.
Population and demographic data sourced from the U.S. Census Bureau American Community Survey (ACS) 5-Year Estimates. ZIP code routing data sourced from the United States Postal Service (USPS).
All San Mateo County Zip Codes
San Mateo County at a Glance
San Mateo County has 57 ZIP codes in this directory: 29 standard delivery ZIPs and 28 PO Box or unique ZIPs that carry no resident population in Census data. The 28 ZIPs with published Census housing data cover 724,829 residents, the largest being 94080 (South San Francisco) with 66,262 people.
The median ZIP in San Mateo County has a household income of $161,447 and a home value of $1,429,950, a price-to-income ratio of 9.0, above the 6.7 California ZIP median. Affordability ranges from 94020 in La Honda at a ratio of 4.3 to 94002 in Belmont, where the median home is above the $2 million Census ceiling. The highest median income is in 94020 (La Honda) at more than $250,000. Median rent across these ZIPs is $2,758 a month.
64% of households in the typical San Mateo County ZIP own their home (statewide ZIP median 64%). 55% of adults hold a bachelor's degree, far above the 31% statewide median. The median poverty rate is 5.4%, far below the 10.8% statewide ZIP median. Overall density is about 1,689 residents per square mile across 429 square miles of ZIP land area.
Medians are taken across the ZIP codes listed below (each ZIP weighted equally); PO Box and no-data ZIPs are excluded. Definitions on the methodology page; statewide comparisons in the 2026 California ZIP Code Affordability Report.
San Mateo County Zip Code Map
Interactive map of San Mateo County, California zip codes.