ZIP Code 94003 — Belmont, California
📍 ZIP code 94003 is in Belmont, San Mateo County, California.
ZIP code 94003 is a PO Box ZIP code assigned by the U.S. Postal Service in Belmont, San Mateo County, California. It serves post office boxes at a Belmont post office rather than street addresses, which is why the Census Bureau reports no resident population, income or housing figures for it. Mail addressed to 94003 is handled in the Pacific Time Zone and the local area code is 650. The demographic profile of the surrounding community is on the standard delivery ZIP pages for Belmont listed below.
Why there are no demographics for 94003
The Census Bureau publishes demographics for ZIP Code Tabulation Areas (ZCTAs), which are built from populated census blocks. A PO Box ZIP like 94003 has no delivery territory of its own, so there is no ZCTA and no population, income, housing or education estimate to report. This is normal: San Mateo County and the rest of California have hundreds of PO Box and unique ZIPs of this kind.
For the community around Belmont, use the delivery ZIPs that do carry Census data:
How ZIPs and ZCTAs differ is explained on the methodology page.
Nearby Zip Codes
Cities & Places Served
ZIP code 94003 primarily serves Belmont in San Mateo County, California.