78231 ZIP Code, San Antonio, TX

78231 is a ZIP code in San Antonio, Texas in Bexar County. It covers 4.1 square miles of land, centered about 11 miles north of downtown San Antonio. The closest ZIP codes are 78248, 78230 and 78232. 9,744 people live here in 3,978 households. At about 2,383 people per square mile it has suburban density, and owners and renters are mixed (66% own). Median household income is $109,183, above the Texas median of $78,476.

Quick facts

Key figures

MeasureValue
Residents9,744
Households3,978
Median household income$109,183
Income per person$57,828
Median age41.2
Homeowners66.2%
Median home value$401,800
Median rent$1,393
Bachelor's degree or higher65.7%
Average commute (minutes)20.5
Households with kids under 1829.0%
Moved in the past year13.6%
Below the poverty line5.8%
Broadband internet94.2%
Speak a non-English language at home19.9%

Household income

% of householdsValue
<$10K3.3%
$10–15K2.0%
$15–25K2.9%
$25–35K3.4%
$35–50K12.0%
$50–75K13.7%
$75–100K7.7%
$100–150K24.3%
$150–200K12.0%
$200K+18.6%

Age

% of all residentsValue
<107.6%
10–1917.1%
20–248.5%
25–3413.0%
35–449.7%
45–5412.2%
55–6411.4%
65–749.4%
75+11.0%

Tenure

% of housing unitsValue
Owned, with mortgage36.4%
Owned outright28.4%
Rented32.7%
Vacant2.6%

Type of building

% of housing unitsValue
Detached house71.8%
Townhome0.0%
2–4 units0.8%
5–19 units11.5%
20+ units14.8%
Mobile / other1.1%

Businesses in 78231

359 business establishments with 4,196 employees (ZIP Codes Business Patterns 2023).

EDDM carrier routes

78231 has 6 USPS carrier routes with 4,063 residential and 370 business mailboxes. Open the EDDM route map.

Carrier routes in 78231

78231 has 6 USPS carrier routes (6 city (C)) with 4,063 residential and 370 business mailboxes. Routes range from 344 homes (C007) to 982 homes (C022); the median route has 680 homes. The Census counted 3,978 households in 78231 (2020–2024 average); USPS counts current mailboxes, including new and vacant homes.

Homes per routeRoutes
1–2490
250–4991
500–7493
750–9992
1,000–1,4990
1,500+0

Best routes in 78231 for…

Highest income

For bigger-ticket offers: remodeling, pools, financial planning, private schools.

  1. Route C019 — Est. median household income $139,279, 615 homes
  2. Route C022 — Est. median household income $120,300, 982 homes
  3. Route C005 — Est. median household income $117,488, 690 homes
  4. Route C007 — Est. median household income $114,366, 344 homes
  5. Route C036 — Est. median household income $107,983, 670 homes

Select these 5 routes on the route map

Often mailed by: Home services EDDM, Real estate EDDM postcards, Landscaping and lawn care mailers

Most families with kids

For tutoring, youth sports, pediatric dental, child care and family dining.

  1. Route C022 — Est. families with children under 18 38.4%, 982 homes
  2. Route C005 — Est. families with children under 18 37.3%, 690 homes
  3. Route C036 — Est. families with children under 18 34.5%, 670 homes
  4. Route C037 — Est. families with children under 18 26.2%, 762 homes
  5. Route C019 — Est. families with children under 18 23.2%, 615 homes

Select these 5 routes on the route map

Often mailed by: Dental practice EDDM, Healthcare and clinic mailers

Most homeowners

Owners decide on roofs, HVAC, lawns, solar and insurance; renters usually can't.

  1. Route C022 — Est. owner-occupied homes 93.4%, 982 homes
  2. Route C005 — Est. owner-occupied homes 86.7%, 690 homes
  3. Route C036 — Est. owner-occupied homes 77.0%, 670 homes
  4. Route C019 — Est. owner-occupied homes 73.4%, 615 homes
  5. Route C007 — Est. owner-occupied homes 47.7%, 344 homes

Select these 5 routes on the route map

Often mailed by: Roofing direct mail, HVAC postcards

Most new movers

New residents are still choosing a dentist, a gym and a lawn service.

  1. Route C007 — Est. residents who moved in the past year 23.2%, 344 homes
  2. Route C037 — Est. residents who moved in the past year 18.9%, 762 homes
  3. Route C019 — Est. residents who moved in the past year 11.9%, 615 homes
  4. Route C036 — Est. residents who moved in the past year 8.2%, 670 homes
  5. Route C005 — Est. residents who moved in the past year 7.8%, 690 homes

Select these 5 routes on the route map

Often mailed by: Restaurant EDDM menus and offers, Gym and fitness mailers

Newest homes

Newer subdivisions: landscaping, window treatments, fencing, security, home warranties.

  1. Route C007 — Est. homes built 2010 or later 49.1%, 344 homes
  2. Route C019 — Est. homes built 2010 or later 29.7%, 615 homes
  3. Route C037 — Est. homes built 2010 or later 7.9%, 762 homes
  4. Route C036 — Est. homes built 2010 or later 4.2%, 670 homes
  5. Route C022 — Est. homes built 2010 or later 2.5%, 982 homes

Select these 5 routes on the route map

Most businesses

For B2B offers: office supplies, cleaning, IT, catering and commercial services.

  1. Route C007 — USPS business mailboxes 147, 344 homes
  2. Route C037 — USPS business mailboxes 125, 762 homes
  3. Route C036 — USPS business mailboxes 74, 670 homes
  4. Route C022 — USPS business mailboxes 18, 982 homes
  5. Route C019 — USPS business mailboxes 6, 615 homes

Select these 5 routes on the route map

Every carrier route in 78231

RouteTypeHomesBusinessesEst. median incomeEst. ownersEst. families with kidsEst. moved in past year
C005City6900$117,48886.7%37.3%7.8%
C007City344147$114,36647.7%18.8%23.2%
C019City6156$139,27973.4%23.2%11.9%
C022City98218$120,30093.4%38.4%7.4%
C036City67074$107,98377.0%34.5%8.2%
C037City762125$65,57041.0%26.2%18.9%

Income, owners, families and movers are estimates for each route (how we estimate them); mailbox counts are current USPS figures. Open 78231 on the EDDM route map.

How route demographics are estimated

Mailbox counts come from USPS; demographics are estimates

The number of homes and businesses on each carrier route is the current USPS EDDM count. The Census Bureau does not publish figures for carrier routes, so income, homeownership, ages, families, movers and housing age on a route are EDDM2GO estimates built from Census block groups (neighborhood areas of roughly 600 to 3,000 people).

How a route gets its figures: the block-group length-share method

We trace each route's streets every 25 meters and record which block group each stretch falls in. The route's homes are spread along its streets in proportion to length, so a route with 60% of its street length in one block group is assumed to have 60% of its homes there. Each block group then contributes its Census counts in proportion to the share of its housing units that sit on the route (capped at the whole block group). Medians are recalculated from the combined income, home-value and age brackets, the way the Census Bureau computes them, not averaged.

Margins of error

Census survey figures carry a margin of error at 90% confidence; we carry it through the calculation and show it as ±. Our margins treat the route-to-block-group split as exact, so the real uncertainty is larger. Routes with fewer than 100 estimated households, large margins, or streets we could not place are flagged.

Different years

USPS mailbox counts are current. Census figures are 5-year averages for 2020–2024, so a new subdivision may have more homes on the route today than the Census counted. Use the route figures to compare routes with each other, not as an exact head count.

Why some routes show identical figures

Two routes that run through the same block group get the same percentages and medians, because the Census publishes one set of figures for the whole block group. Their mailbox counts still differ, and those are exact.

Route and mailbox counts: USPS EDDM route data. Route demographics: EDDM2GO estimates from U.S. Census Bureau American Community Survey 5-year block-group data (2020–2024) and 2024 cartographic block-group boundaries. This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.

Nearby ZIP codes

Areas that include 78231

Where it ranks

Mail every home in 78231

Route counts on this page price as Full Service 6.5 × 9 postcards: we print, bundle by carrier route and hand the mailing to USPS. Prefer to take it to the Post Office yourself? Print only costs less and you pay postage at drop-off.

San Antonio EDDM mailing

EDDM guides

ZIP code statistics describe the Census ZIP Code Tabulation Area (ZCTA) 78231, which approximates the USPS ZIP code area. Census figures: American Community Survey 5-year estimates, 2020–2024.

Frequently asked questions

What city is 78231 in?
78231 is a San Antonio, TX mailing address. By land area, 59% lies inside Shavano Park and 41% lies inside San Antonio.
What county is 78231 in?
78231 is in Bexar County.
What is the population of 78231?
About 9,744 people (±1,117), according to the Census Bureau's American Community Survey 5-year estimates for 2020–2024. The 2020 Census counted 8,993.
What is the median household income in 78231?
$109,183 (±$12,628), compared with $78,476 for Texas as a whole. Half the households in the ZIP code earn more and half earn less.
How many carrier routes and mailboxes are in 78231?
6 USPS carrier routes with 4,063 residential and 370 business mailboxes (4,434 in all), from the route data stored by EDDM2GO. An EDDM mailing can target any combination of these routes.
What ZIP codes are near 78231?
The closest, measured center to center: 78248 (1.2 mi, San Antonio), 78230 (2.5 mi, San Antonio), 78232 (4 mi, San Antonio), 78216 (4.2 mi, San Antonio), 78249 (4.5 mi, San Antonio) and 78213 (4.6 mi, San Antonio).

This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.