San Marcos, TX ZIP Codes
2 ZIP codes serve San Marcos, Texas: 78666 and 78656. Together they are home to 91,430 residents in 34,925 households. Median household income ranges from $54,737 in 78666 to $81,346 in 78656.
San Marcos city limits (Census)
| Measure | Census figure |
|---|---|
| Residents | 70,897 |
| Households | 28,013 |
| Median household income | $51,281 |
| Median home value | $310,400 |
| Median age | 25.5 |
| Median rent | $1,322 |
All 2 ZIP codes together
| Measure | Value |
|---|---|
| Residents (sum of ZIP codes) | 91,430 |
| Households (sum of ZIP codes) | 34,925 |
| Median household income, range across ZIP codes | $54,737 (78666) to $81,346 (78656) |
| Household-weighted average of ZIP medians (an approximation, not a true median) | $55,481 |
| Homeowners | 39.0% |
| Households with kids under 18 | 20.9% |
| Moved in the past year | 28.1% |
| Carrier routes in EDDM2GO's route library | 46 routes, 43,690 homes (2 of 2 ZIP codes) |
Top facts
- Highest median household income in San Marcos: 78656 ($81,346)
- Most residents: 78666 (88,583 people)
- Highest homeownership: 78656 (69.2% own their home)
- Most households with kids: 78656 (28.3% of households)
- Most new movers: 78666 (28.8% moved in last year)
- Youngest median age: 78666 (26.9 years)
- Highest median home value: 78666 ($306,700)
Every ZIP code in San Marcos
| ZIP | Mailing city | Residents | Households | Median income | Home value | Homeowners | With kids | New movers | Carrier routes | Mailboxes | Why listed |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 78666 | San Marcos | 88,583 | 33,949 | $54,737 | $306,700 | 38.1% | 20.7% | 28.8% | 43 | 43,040 | 17% of its land; mailing city |
| 78656 | Maxwell | 2,847 | 976 | $81,346 | $238,100 | 69.2% | 28.3% | 5.0% | 3 | 3,100 | 11% of its land |
A ZIP code is listed for San Marcos when at least 10% of its land lies inside San Marcos city limits, when it holds at least 10% of the place's land, or when its USPS mailing city is San Marcos. The table shows which applies. Totals add up whole ZIP codes, so they include any parts outside San Marcos.
Counties
- Hays County — 8 ZIP codes
- Caldwell County — 11 ZIP codes
Nearby cities sharing these ZIP codes
- Kyle — 2 ZIP codes
Metro maps
- Austin ZIP code map — 89 ZIP codes
Price a mailing to San Marcos ZIP codes
EDDM guides
Pick carrier routes on the EDDM route map
Frequently asked questions
- What ZIP codes are in San Marcos, TX?
- 78666 and 78656. A ZIP code is listed for San Marcos when at least 10% of its land lies inside San Marcos city limits, when it holds at least 10% of the place's land, or when its USPS mailing city is San Marcos.
- What is the population of San Marcos, TX?
- The Census Bureau counts 70,897 residents inside San Marcos city limits (ACS 2020–2024). The 2 ZIP codes that serve San Marcos hold 91,430 residents in all.
- What is the median household income in San Marcos, TX?
- $51,281 inside San Marcos city limits, per the Census Bureau. Across its ZIP codes the medians run from $54,737 to $81,346.
- Which San Marcos ZIP code has the highest median household income?
- 78656, at $81,346, among ZIP codes with at least 1,000 residents.
- How many carrier routes and mailboxes are in San Marcos, TX?
- For the 2 of 2 ZIP codes in EDDM2GO's stored route library: 46 carrier routes reaching 43,690 residential and 2,448 business mailboxes.
This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.