San Marcos, TX 78666 ZIP Code Profile

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San Marcos, TX

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ZIP Code 78666: Basic Data & USPS Preferred City Name

Preferred Name, USPS
San Marcos, TX 78666

  • ZIP Code Type: STANDARD
  • Businesses Addresses: 2,170
  • Single Family Addresses: 16,860
  • Multi-Family Addresses: 10,179
  • County: Hays County
  • Centroid: Latitude 29.883, Longitude -97.945
  • Time Zone: Central Time Zone (UTC -6 hours)
  • Observes DST: Yes

ZIP Code 78666 has segments in 4 Counties (Caldwell, Comal, Guadalupe, Hays).

Neighborhood Data

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78666 ZIP Code Map

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San Marcos, TX 78666 Data & Demographics (As of July 1, 2017)


Total Population 77,458
Daytime Population: Workers 39,176
Daytime Population: Residents 42,788
Total Daytime Population (TDP) 81,964
Ratio TDP/Total Population1 1.06
Population in Households 68,641
Population in Familes 40,710
Population in Group Qrtrs 8,817
Population Density2 414
Diversity Index3 72


Median Household Income $39,026
Average Household Income $57,103
Per Capita Income $23,341


Total Housing Units 30,210 (100%)
Owner Occupied HU 9,810 (32.5%)
Renter Occupied HU 18,412 (60.9%)
Vacant Housing Units 1,988 ( 6.6%)
Median Home Value $161,916
Average Home Value $201,957


Total Households 28,222
Average Household Size 2.43
Family Households 12,793
Average Family Size 3
  1. If the ratio of the TDP to Total Population is greater than 1, the location gains population during the day when commuting workers are present. If the ratio is less than 1, the location is more of a bedroom community where people commute to another place for work.
  2. Population Density = Total Population per square mile.
  3. The Diversity Index is a scale of 0 to 100 that represents the likelihood that two persons, chosen at random from the same area, belong to different race or ethnic groups. If an area's entire population belongs to one race AND one ethnic group, then the area has zero diversity. An area's diversity index increases to 100 when the population is evenly divided into two or more race/ethnic groups.


2010-2017 2017-2022
Population 2.71% 3.11%
Households 2.94% 3.55%
Families 2.36% 3.13%
Median Household Income   1.71%
Per Capita Income   2.4%

San Marcos, TX 78666 - Peer Comparisons by Rank and Percentile

The table below compares 78666 to the other 1,848 ZIP Codes in Texas by rank and percentile using July 1, 2017 data. The location Ranked # 1 has the highest value. A location that ranks higher than 75% of its peers would be in the 75th percentile of the peer group.

Variable Description Rank Percentile
Total Population # 23 99th
Population Density # 657 65th
Diversity Index # 363 80th
Median Household Income # 1512 18th
Per Capita Income # 1193 35th

Additional comparisons and rankings can be made with a VERY EASY TO USE Texas Census Data Comparison Tool.

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