78664 ZIP Code, Round Rock, TX
78664 is a ZIP code in Round Rock, Texas — mostly in Williamson County (86% of its land), with smaller parts in Travis County. It covers 17 square miles of land, centered about 17 miles north of downtown Austin. The closest ZIP codes are 78665, 78728 and 78681. 62,060 people live here in 23,484 households, more than in 9 of every 10 Texas ZIP codes. At about 3,736 people per square mile it has suburban density, and owners and renters are mixed (54% own). Median household income is $87,417, above the Texas median of $78,476.
Quick facts
- Mailing city: Round Rock, TX
- County: Williamson County
- Metro area: Austin
- Land area: 17 sq mi
- Population: 62,060
- Median household income: $87,417
- Carrier routes: 30 (23,993 homes)
Key figures
| Measure | Value |
|---|---|
| Residents | 62,060 |
| Households | 23,484 |
| Median household income | $87,417 |
| Income per person | $43,876 |
| Median age | 35.1 |
| Homeowners | 53.7% |
| Median home value | $358,200 |
| Median rent | $1,692 |
| Bachelor's degree or higher | 36.4% |
| Average commute (minutes) | 25.6 |
| Households with kids under 18 | 31.6% |
| Moved in the past year | 17.2% |
| Below the poverty line | 10.2% |
| Broadband internet | 95.4% |
| Speak a non-English language at home | 31.9% |
Household income
| % of households | Value |
|---|---|
| <$10K | 2.4% |
| $10–15K | 1.8% |
| $15–25K | 3.4% |
| $25–35K | 4.5% |
| $35–50K | 9.5% |
| $50–75K | 21.1% |
| $75–100K | 13.2% |
| $100–150K | 19.6% |
| $150–200K | 11.5% |
| $200K+ | 12.9% |
Age
| % of all residents | Value |
|---|---|
| <10 | 10.5% |
| 10–19 | 14.5% |
| 20–24 | 8.3% |
| 25–34 | 16.6% |
| 35–44 | 15.8% |
| 45–54 | 12.7% |
| 55–64 | 10.8% |
| 65–74 | 6.8% |
| 75+ | 4.0% |
Tenure
| % of housing units | Value |
|---|---|
| Owned, with mortgage | 36.0% |
| Owned outright | 15.6% |
| Rented | 44.2% |
| Vacant | 4.1% |
Type of building
| % of housing units | Value |
|---|---|
| Detached house | 62.7% |
| Townhome | 5.0% |
| 2–4 units | 8.1% |
| 5–19 units | 12.7% |
| 20+ units | 11.4% |
| Mobile / other | 0.0% |
Businesses in 78664
1,841 business establishments with 28,470 employees (ZIP Codes Business Patterns 2023).
- Retail Trade: 284
- Professional, Scientific, and Technical Services: 264
- Health Care and Social Assistance: 202
- Accommodation and Food Services: 188
- Construction: 176
- Other Services (except Public Administration): 157
- Finance and Insurance: 110
- Real Estate and Rental and Leasing: 106
EDDM carrier routes
78664 has 30 USPS carrier routes with 23,993 residential and 1,955 business mailboxes. Open the EDDM route map.
Carrier routes in 78664
78664 has 30 USPS carrier routes (9 city (C), 21 rural (R)) with 23,993 residential and 1,955 business mailboxes. Routes range from 7 homes (R071) to 1,266 homes (C035); the median route has 839 homes. The Census counted 23,484 households in 78664 (2020–2024 average); USPS counts current mailboxes, including new and vacant homes.
| Homes per route | Routes |
|---|---|
| 1–249 | 2 |
| 250–499 | 3 |
| 500–749 | 5 |
| 750–999 | 12 |
| 1,000–1,499 | 8 |
| 1,500+ | 0 |
Best routes in 78664 for…
Highest income
For bigger-ticket offers: remodeling, pools, financial planning, private schools.
- Route R023 — Est. median household income $163,970, 825 homes
- Route R008 — Est. median household income $155,210, 496 homes
- Route R043 — Est. median household income $148,494, 691 homes
- Route R012 — Est. median household income $140,440, 629 homes
- Route R007 — Est. median household income $126,625, 721 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.
- Route R005 — Est. families with children under 18 48.0%, 954 homes
- Route R032 — Est. families with children under 18 44.8%, 718 homes
- Route R031 — Est. families with children under 18 43.3%, 1,044 homes
- Route R043 — Est. families with children under 18 43.0%, 691 homes
- Route R058 — Est. families with children under 18 42.8%, 976 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.
- Route R008 — Est. owner-occupied homes 91.6%, 496 homes
- Route R012 — Est. owner-occupied homes 91.4%, 629 homes
- Route R023 — Est. owner-occupied homes 89.6%, 825 homes
- Route R043 — Est. owner-occupied homes 86.7%, 691 homes
- Route R007 — Est. owner-occupied homes 84.9%, 721 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.
- Route R048 — Est. residents who moved in the past year 30.6%, 774 homes
- Route C002 — Est. residents who moved in the past year 27.3%, 918 homes
- Route C029 — Est. residents who moved in the past year 26.1%, 330 homes
- Route C035 — Est. residents who moved in the past year 23.8%, 1,266 homes
- Route R002 — Est. residents who moved in the past year 23.8%, 885 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.
- Route R032 — Est. homes built 2010 or later 54.1%, 718 homes
- Route R017 — Est. homes built 2010 or later 49.0%, 1,107 homes
- Route R054 — Est. homes built 2010 or later 45.9%, 854 homes
- Route R058 — Est. homes built 2010 or later 43.0%, 976 homes
- Route R031 — Est. homes built 2010 or later 41.5%, 1,044 homes
Select these 5 routes on the route map
Most businesses
For B2B offers: office supplies, cleaning, IT, catering and commercial services.
- Route C006 — USPS business mailboxes 358, 378 homes
- Route C029 — USPS business mailboxes 336, 330 homes
- Route R032 — USPS business mailboxes 229, 718 homes
- Route R002 — USPS business mailboxes 156, 885 homes
- Route R074 — USPS business mailboxes 119, 96 homes
Select these 5 routes on the route map
Every carrier route in 78664
| Route | Type | Homes | Businesses | Est. median income | Est. owners | Est. families with kids | Est. moved in past year |
|---|---|---|---|---|---|---|---|
| C001 | City | 543 | 108 | $60,394 | 30.5% | 22.0% | 15.2% |
| C002 | City | 918 | 21 | $65,558 | 36.0% | 30.3% | 27.3% |
| C005 | City | 1,265 | 47 | $73,736 | 48.7% | 25.2% | 20.0% |
| C006 | City | 378 | 358 | $76,320 | 32.3% | 17.8% | 20.9% |
| C023 | City | 1,021 | 74 | $78,893 | 50.3% | 22.7% | 18.6% |
| C026 | City | 1,201 | 6 | $74,795 | 51.2% | 34.8% | 16.0% |
| C028 | City | 779 | 105 | $67,359 | 36.5% | 23.7% | 21.5% |
| C029 | City | 330 | 336 | $60,762 | 27.2% | 27.2% | 26.1% |
| C035 | City | 1,266 | 11 | $65,731 | 43.7% | 31.3% | 23.8% |
| R002 | Rural | 885 | 156 | $102,421 | 46.4% | 20.9% | 23.8% |
| R005 | Rural | 954 | 0 | $117,407 | 65.3% | 48.0% | 10.3% |
| R007 | Rural | 721 | 39 | $126,625 | 84.9% | 39.0% | 7.8% |
| R008 | Rural | 496 | 16 | $155,210 | 91.6% | 28.4% | 4.4% |
| R012 | Rural | 629 | 12 | $140,440 | 91.4% | 37.7% | 4.6% |
| R014 | Rural | 1,031 | 7 | $105,843 | 56.7% | 42.4% | 17.5% |
| R017 | Rural | 1,107 | 73 | $99,470 | 55.5% | 23.1% | 18.2% |
| R023 | Rural | 825 | 1 | $163,970 | 89.6% | 39.7% | 10.4% |
| R026 | Rural | 833 | 3 | $88,994 | 75.2% | 35.6% | 16.1% |
| R027 | Rural | 919 | 10 | $122,894 | 54.4% | 39.6% | 21.2% |
| R031 | Rural | 1,044 | 6 | $119,790 | 62.0% | 43.3% | 6.7% |
| R032 | Rural | 718 | 229 | $98,757 | 60.1% | 44.8% | 7.4% |
| R039 | Rural | 1,054 | 90 | $72,590 | 44.9% | 20.5% | 22.7% |
| R043 | Rural | 691 | 41 | $148,494 | 86.7% | 43.0% | 20.7% |
| R048 | Rural | 774 | 1 | $91,832 | 59.6% | 41.9% | 30.6% |
| R054 | Rural | 854 | 2 | $88,423 | 62.6% | 33.4% | 9.0% |
| R058 | Rural | 976 | 22 | $92,110 | 37.1% | 42.8% | 10.7% |
| R062 | Rural | 838 | 31 | $121,587 | 78.4% | 40.8% | 22.5% |
| R071 | Rural | 7 | 3 | $124,628 | 87.5% | 25.5% | 3.7% |
| R072 | Rural | 840 | 28 | $103,886 | 40.8% | 26.7% | 17.3% |
| R074 | Rural | 96 | 119 | $111,367 | 56.7% | 29.0% | 12.1% |
Income, owners, families and movers are estimates for each route (how we estimate them); mailbox counts are current USPS figures. Open 78664 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
- 78665 — Round Rock city, TX (3.1 mi)
- 78728 — Austin city, TX (4.3 mi)
- 78681 — Round Rock city, TX (4.8 mi)
- 78660 — Pflugerville city, TX (5.5 mi)
- 78717 — Austin city, TX (6.4 mi)
- 78727 — Austin city, TX (6.7 mi)
- 78634 — Hutto city, TX (7.2 mi)
- 78729 — Austin city, TX (7.3 mi)
Areas that include 78664
- Round Rock, TX ZIP codes — 3 ZIP codes
- Travis County ZIP codes — 56 ZIP codes
- Williamson County ZIP codes — 24 ZIP codes
- Austin ZIP code map — 89 ZIP codes
- Texas ZIP code data
Where it ranks
- No. 24 of 83: highest share of residents who moved in during the past year in the Austin area
- No. 6 of 22: highest share of residents who moved in during the past year in Williamson County
- No. 7 of 22: lowest median age in Williamson County
Mail every home in 78664
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) 78664, which approximates the USPS ZIP code area. Census figures: American Community Survey 5-year estimates, 2020–2024.
Frequently asked questions
- What city is 78664 in?
- 78664 is a Round Rock, TX mailing address. By land area, 72% lies inside Round Rock and 10% lies inside Pflugerville; the rest is outside any Census-defined city or community.
- What county is 78664 in?
- 78664 is mostly in Williamson County (86% of its land), with smaller parts in Travis County.
- What is the population of 78664?
- About 62,060 people (±2,566), according to the Census Bureau's American Community Survey 5-year estimates for 2020–2024. The 2020 Census counted 60,287.
- What is the median household income in 78664?
- $87,417 (±$6,353), 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 78664?
- 30 USPS carrier routes with 23,993 residential and 1,955 business mailboxes (25,949 in all), from the route data stored by EDDM2GO. An EDDM mailing can target any combination of these routes.
- What ZIP codes are near 78664?
- The closest, measured center to center: 78665 (3.1 mi, Round Rock), 78728 (4.3 mi, Austin), 78681 (4.8 mi, Round Rock), 78660 (5.5 mi, Pflugerville), 78717 (6.4 mi, Austin) and 78727 (6.7 mi, Austin).
This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.