San Marcos California ZIP Codes

San Marcos holds 4 ZIP codes, all inside one county and one postal prefix.

We do not publish a delivery type (standard, PO box, unique) or a neighbourhood for each ZIP. USPS delivery-type products are licensed, and no clean-rights source maps ZIP codes to neighbourhoods — so the San Marcos codes above are listed without a column we would have to invent.

Scope every ZIP code recorded for San Marcos. Source GeoNames US postal codes (2026-07 postal dump) and Census 2024 county Gazetteer (2024 Gazetteer). Updated 15 July 2026. ZIP codes are delivery-route groupings, not areas; the boundaries implied by any ZIP map are approximations.

Every San Marcos ZIP code begins 920. Those first three digits identify the sectional center facility that processes mail for this part of California. Statewide that range covers 64 ZIP codes, so San Marcos accounts for 6% of it.

Every California ZIP prefix and the region it covers →

ZIP codes and area codes are separate systems — one routes mail, the other routes calls — and they do not share boundaries. The codes below serve the same ground San Marcos occupies.

• 442 Area code 442
• 760 Area code 760

San Marcos California area codes in full →

Straight-line distance between place reference points, not driving distance.