78681 ZIP Code, Round Rock, TX

78681 is a ZIP code in Round Rock, Texas in Williamson County. It covers 23 square miles of land, centered about 19 miles north of downtown Austin. The closest ZIP codes are 78717, 78664 and 78665. 56,691 people live here in 20,135 households, more than in 9 of every 10 Texas ZIP codes. At about 2,445 people per square mile it has suburban density, and most homes are owner-occupied (74%). Median household income is $137,819, well above the Texas median of $78,476; 43% of households have children under 18.

Quick facts

Key figures

MeasureValue
Residents56,691
Households20,135
Median household income$137,819
Income per person$59,301
Median age39.3
Homeowners73.9%
Median home value$497,300
Median rent$1,963
Bachelor's degree or higher58.0%
Average commute (minutes)23.6
Households with kids under 1843.0%
Moved in the past year11.6%
Below the poverty line5.5%
Broadband internet95.9%
Speak a non-English language at home27.4%

Household income

% of householdsValue
<$10K2.1%
$10–15K1.3%
$15–25K3.4%
$25–35K2.9%
$35–50K4.5%
$50–75K11.0%
$75–100K9.5%
$100–150K20.1%
$150–200K18.4%
$200K+26.8%

Age

% of all residentsValue
<1012.9%
10–1916.7%
20–244.1%
25–3410.1%
35–4416.9%
45–5417.3%
55–6410.8%
65–747.2%
75+4.1%

Tenure

% of housing unitsValue
Owned, with mortgage48.3%
Owned outright23.4%
Rented25.2%
Vacant3.1%

Type of building

% of housing unitsValue
Detached house81.4%
Townhome1.7%
2–4 units2.8%
5–19 units5.2%
20+ units8.4%
Mobile / other0.6%

Businesses in 78681

1,432 business establishments with 19,609 employees (ZIP Codes Business Patterns 2023).

EDDM carrier routes

78681 has 27 USPS carrier routes with 21,501 residential and 1,186 business mailboxes. Open the EDDM route map.

Carrier routes in 78681

78681 has 27 USPS carrier routes (10 city (C), 17 rural (R)) with 21,501 residential and 1,186 business mailboxes. Routes range from 476 homes (C039) to 1,431 homes (R016); the median route has 720 homes. The Census counted 20,135 households in 78681 (2020–2024 average); USPS counts current mailboxes, including new and vacant homes.

Homes per routeRoutes
1–2490
250–4991
500–74914
750–9998
1,000–1,4994
1,500+0

Best routes in 78681 for…

Highest income

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

  1. Route R040 — Est. median household income $200,000+, 796 homes
  2. Route R018 — Est. median household income $200,000+, 676 homes
  3. Route R044 — Est. median household income $199,218, 584 homes
  4. Route R010 — Est. median household income $188,223, 687 homes
  5. Route R056 — Est. median household income $182,653, 609 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 R003 — Est. families with children under 18 69.8%, 674 homes
  2. Route R040 — Est. families with children under 18 67.9%, 796 homes
  3. Route R056 — Est. families with children under 18 61.4%, 609 homes
  4. Route R044 — Est. families with children under 18 60.0%, 584 homes
  5. Route R010 — Est. families with children under 18 55.5%, 687 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 R003 — Est. owner-occupied homes 99.0%, 674 homes
  2. Route R040 — Est. owner-occupied homes 95.8%, 796 homes
  3. Route C003 — Est. owner-occupied homes 93.5%, 611 homes
  4. Route R056 — Est. owner-occupied homes 93.1%, 609 homes
  5. Route R044 — Est. owner-occupied homes 93.0%, 584 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 R016 — Est. residents who moved in the past year 23.9%, 1,431 homes
  2. Route C039 — Est. residents who moved in the past year 18.6%, 476 homes
  3. Route R009 — Est. residents who moved in the past year 18.0%, 819 homes
  4. Route R033 — Est. residents who moved in the past year 17.9%, 1,346 homes
  5. Route R001 — Est. residents who moved in the past year 16.5%, 689 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 R055 — Est. homes built 2010 or later 96.6%, 722 homes
  2. Route R056 — Est. homes built 2010 or later 48.6%, 609 homes
  3. Route R044 — Est. homes built 2010 or later 34.5%, 584 homes
  4. Route R040 — Est. homes built 2010 or later 31.2%, 796 homes
  5. Route R067 — Est. homes built 2010 or later 30.9%, 831 homes

Select these 5 routes on the route map

Most businesses

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

  1. Route C039 — USPS business mailboxes 295, 476 homes
  2. Route C004 — USPS business mailboxes 215, 637 homes
  3. Route R016 — USPS business mailboxes 132, 1,431 homes
  4. Route C007 — USPS business mailboxes 113, 507 homes
  5. Route C024 — USPS business mailboxes 88, 720 homes

Select these 5 routes on the route map

Every carrier route in 78681

RouteTypeHomesBusinessesEst. median incomeEst. ownersEst. families with kidsEst. moved in past year
C003City6111$136,97693.5%30.1%8.1%
C004City637215$82,69653.9%24.9%10.7%
C007City507113$124,13579.7%29.8%10.8%
C008City59812$110,81285.2%25.0%9.0%
C022City1,1700$176,09789.4%46.2%8.9%
C024City72088$88,32438.1%33.1%10.0%
C025City1,24848$120,71878.1%38.0%11.1%
C027City71282$162,61686.6%50.4%10.7%
C031City8601$136,02079.7%36.1%9.0%
C039City476295$112,90858.9%42.8%18.6%
R001Rural68975$140,87977.7%39.0%16.5%
R003Rural6745$161,37799.0%69.8%1.0%
R004Rural6011$158,66479.4%36.5%9.7%
R009Rural8190$128,73373.0%39.0%18.0%
R010Rural6877$188,22390.7%55.5%3.4%
R016Rural1,431132$74,41624.5%14.7%23.9%
R018Rural6760$200,000+92.4%50.2%14.0%
R019Rural8170$117,63167.9%52.6%10.9%
R021Rural8902$153,48372.1%45.4%14.6%
R033Rural1,34673$83,52632.8%23.8%17.9%
R034Rural8001$178,94282.5%53.9%7.7%
R040Rural7961$200,000+95.8%67.9%6.9%
R041Rural9909$173,63284.1%53.8%11.1%
R044Rural5841$199,21893.0%60.0%11.2%
R055Rural7220$137,61988.3%33.6%13.3%
R056Rural6099$182,65393.1%61.4%16.0%
R067Rural83115$158,04086.0%52.0%8.7%

Income, owners, families and movers are estimates for each route (how we estimate them); mailbox counts are current USPS figures. Open 78681 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 78681

Where it ranks

Mail every home in 78681

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.

EDDM guides

ZIP code statistics describe the Census ZIP Code Tabulation Area (ZCTA) 78681, which approximates the USPS ZIP code area. Census figures: American Community Survey 5-year estimates, 2020–2024.

Frequently asked questions

What city is 78681 in?
78681 is a Round Rock, TX mailing address. By land area, 45% lies inside Round Rock, 18% lies inside Brushy Creek and 1% lies inside Austin; the rest is outside any Census-defined city or community.
What county is 78681 in?
78681 is in Williamson County.
What is the population of 78681?
About 56,691 people (±2,713), according to the Census Bureau's American Community Survey 5-year estimates for 2020–2024. The 2020 Census counted 57,503.
What is the median household income in 78681?
$137,819 (±$8,741), 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 78681?
27 USPS carrier routes with 21,501 residential and 1,186 business mailboxes (22,690 in all), from the route data stored by EDDM2GO. An EDDM mailing can target any combination of these routes.
What ZIP codes are near 78681?
The closest, measured center to center: 78717 (4.2 mi, Austin), 78664 (4.8 mi, Round Rock), 78665 (4.8 mi, Round Rock), 78728 (6.3 mi, Austin), 78729 (6.3 mi, Austin) and 78613 (6.6 mi, Cedar Park).

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