Plain

City ZIP codes · California

San Marcos, CA ZIP Codes

4 ZIP codes use the postal name San Marcos, California (Census 2020 ZCTAs and GeoNames postal codes, October 2026): 3 residential and 1 for PO boxes or a single organization. Median household income runs from $96,771 in 92069 to $120,268 in 92078, 1.2 times as much (Census Bureau, ACS 2020-2024). San Marcos's most populous ZIP code is 92078, with 53,605 people (ACS 2020-2024); 79% of its land is in the city of San Marcos.

  • ACS2020-24
  • Census2020
  • GeoNames2026

Where are San Marcos's ZIP codes?

92069: $97k median household income92078: $120k median household income92096: – median household income92069920789209692069: $97k median household income92078: $120k median household income92096: – median household income92069920789209692069: $97k median household income92078: $120k median household income92096: – median household income9206992078
The 3 residential ZIP codes named San Marcos, shaded by median household income in national fifths (ACS 2020-2024). Select a ZIP to open it. <$54.1k$98.1k+no figure

Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries; ACS 2020-2024 5-year estimates (B19013).

How different are San Marcos's ZIP codes?

The highest median household income is in 92078 ($120,268), the lowest in 92069 ($96,771). Home values run from $800,700 in 92069 to $942,300 in 92078.

Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B19013, B25077, B01003).

All 3 residential ZIP codes of San Marcos

Residential ZIP codes with the postal name San Marcos, CA, largest first (ACS 2020-2024); sort by any column
County
92078 San Diego County 53,605 3,210 $120k $942k
92069 San Diego County 47,335 2,563 $97k $801k
92096 San Diego County no residents 0 – –

Download the 4 ZIP codes as CSV

Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates; 2023 Gazetteer land areas (2020 ZCTAs); town names from simplemaps US ZIP Codes (CC BY 4.0) and GeoNames (CC BY 4.0).

PO Box and single-organization ZIP codes in San Marcos

1 ZIP code named San Marcos has no residential delivery area: post office boxes, or one organization (a large employer, an agency, a university) with its own code. The Census Bureau publishes no figures for them.

San Marcos, CA: ZIP codes without a residential area, for PO boxes or one organization (GeoNames postal codes; USPS does not publish openly which is which)
ZIPCounty
92079San Diego County

Source: GeoNames postal codes (CC BY 4.0); a ZIP code with no Census ZCTA has no residential delivery area.

Which counties do San Marcos's ZIP codes reach?

San Marcos's residential ZIP codes lie in San Diego County.

Which places do San Marcos's ZIP codes cover?

A postal name is not a city limit. By the Census Bureau's places, San Marcos's residential ZIP codes cover San Marcos itself and 2 other places, each listed with the ZIP codes that have at least 5% of their land in it or hold most of the place:

  • Harmony Grove census-designated 92078
  • Lake San Marcos census-designated 92078

Source: U.S. Census Bureau, 2020 ZCTA-to-place relationship file (shares of land).

Which first three digits do San Marcos's ZIP codes use?

The first three digits of a ZIP code name the sectional center, the mail processing plant that sorts it. Every ZIP code of San Marcos starts with 920.

Three-digit prefixes of San Marcos's ZIP codes, the sectional center for each (USPS labeling list L005, effective October 1, 2026) and how many of the prefix's codes are San Marcos's
PrefixSectional centerHereAll codes
920 San Diego, CA (SCF 920) 4 64

Source: U.S. Postal Service, labeling list L005 (3-digit ZIP Code prefix groups, SCF sortation), effective October 1, 2026.