San Quentin, California Zip Codes
📍 San Quentin is in Marin County, California with 2 zip codes; the most populous is 94964.
San Quentin is a USPS city name in Marin County, California with a Census population of approximately 2,054 across its ZIP codes. Marin County as a whole has 42 ZIP codes in this directory. Below you'll find every zip code serving San Quentin with population, income and home value, a map, and the city's affordability profile.
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 Quentin Zip Codes
San Quentin at a Glance
San Quentin has 2 ZIP codes in this directory: 1 standard delivery ZIP and 1 PO Box or unique ZIP that carries no resident population in Census data.
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 Quentin Zip Code Map
Interactive map of San Quentin, California zip codes. Click any marker for details.