78665 ZIP Code, Round Rock, TX
78665 is a ZIP code in Round Rock, Texas in Williamson County. It covers 24 square miles of land, centered about 20 miles north of downtown Austin. The closest ZIP codes are 78664, 78681 and 78634. 66,171 people live here in 24,162 households, more than in 9 of every 10 Texas ZIP codes. At about 2,748 people per square mile it has suburban density, and owners and renters are mixed (61% own). Median household income is $122,680, well above the Texas median of $78,476; 42% of households have children under 18.
Quick facts
- Mailing city: Round Rock, TX
- County: Williamson County
- Metro area: Austin
- Land area: 24 sq mi
- Population: 66,171
- Median household income: $122,680
- Carrier routes: 33 (30,636 homes)
Key figures
| Measure | Value |
|---|---|
| Residents | 66,171 |
| Households | 24,162 |
| Median household income | $122,680 |
| Income per person | $56,191 |
| Median age | 35.5 |
| Homeowners | 61.4% |
| Median home value | $474,100 |
| Median rent | $1,938 |
| Bachelor's degree or higher | 53.6% |
| Average commute (minutes) | 27.8 |
| Households with kids under 18 | 42.1% |
| Moved in the past year | 22.8% |
| Below the poverty line | 4.7% |
| Broadband internet | 97.3% |
| Speak a non-English language at home | 26.9% |
Household income
| % of households | Value |
|---|---|
| <$10K | 3.9% |
| $10–15K | 1.0% |
| $15–25K | 2.0% |
| $25–35K | 4.0% |
| $35–50K | 6.2% |
| $50–75K | 10.4% |
| $75–100K | 13.2% |
| $100–150K | 21.0% |
| $150–200K | 15.5% |
| $200K+ | 22.8% |
Age
| % of all residents | Value |
|---|---|
| <10 | 14.8% |
| 10–19 | 13.3% |
| 20–24 | 6.6% |
| 25–34 | 14.3% |
| 35–44 | 17.1% |
| 45–54 | 14.7% |
| 55–64 | 8.8% |
| 65–74 | 6.9% |
| 75+ | 3.6% |
Tenure
| % of housing units | Value |
|---|---|
| Owned, with mortgage | 45.1% |
| Owned outright | 13.2% |
| Rented | 36.2% |
| Vacant | 5.6% |
Type of building
| % of housing units | Value |
|---|---|
| Detached house | 72.5% |
| Townhome | 0.5% |
| 2–4 units | 1.2% |
| 5–19 units | 10.2% |
| 20+ units | 15.4% |
| Mobile / other | 0.1% |
Businesses in 78665
981 business establishments with 16,807 employees (ZIP Codes Business Patterns 2023).
- Professional, Scientific, and Technical Services: 163
- Health Care and Social Assistance: 145
- Construction: 101
- Other Services (except Public Administration): 94
- Accommodation and Food Services: 90
- Retail Trade: 83
- Administrative and Support and Waste Management and Remediation Services: 67
- Real Estate and Rental and Leasing: 60
EDDM carrier routes
78665 has 33 USPS carrier routes with 30,636 residential and 874 business mailboxes. Open the EDDM route map.
Carrier routes in 78665
78665 has 33 USPS carrier routes (1 city (C), 32 rural (R)) with 30,636 residential and 874 business mailboxes. Routes range from 554 homes (R068) to 1,490 homes (R006); the median route has 835 homes. The Census counted 24,162 households in 78665 (2020–2024 average); USPS counts current mailboxes, including new and vacant homes.
| Homes per route | Routes |
|---|---|
| 1–249 | 0 |
| 250–499 | 0 |
| 500–749 | 8 |
| 750–999 | 13 |
| 1,000–1,499 | 12 |
| 1,500+ | 0 |
Best routes in 78665 for…
Highest income
For bigger-ticket offers: remodeling, pools, financial planning, private schools.
- Route R053 — Est. median household income $200,000+, 825 homes
- Route R022 — Est. median household income $192,863, 680 homes
- Route R025 — Est. median household income $181,968, 773 homes
- Route R049 — Est. median household income $162,803, 879 homes
- Route R037 — Est. median household income $160,962, 666 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 R053 — Est. families with children under 18 72.7%, 825 homes
- Route R025 — Est. families with children under 18 66.7%, 773 homes
- Route R049 — Est. families with children under 18 58.0%, 879 homes
- Route R057 — Est. families with children under 18 57.2%, 652 homes
- Route R022 — Est. families with children under 18 54.9%, 680 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 R049 — Est. owner-occupied homes 91.4%, 879 homes
- Route R022 — Est. owner-occupied homes 90.4%, 680 homes
- Route R053 — Est. owner-occupied homes 86.0%, 825 homes
- Route R025 — Est. owner-occupied homes 85.3%, 773 homes
- Route R011 — Est. owner-occupied homes 85.2%, 679 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 C036 — Est. residents who moved in the past year 46.3%, 1,309 homes
- Route R042 — Est. residents who moved in the past year 42.2%, 1,325 homes
- Route R050 — Est. residents who moved in the past year 35.0%, 1,058 homes
- Route R013 — Est. residents who moved in the past year 30.5%, 1,146 homes
- Route R028 — Est. residents who moved in the past year 29.3%, 795 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 R053 — Est. homes built 2010 or later 95.9%, 825 homes
- Route R060 — Est. homes built 2010 or later 93.0%, 974 homes
- Route R063 — Est. homes built 2010 or later 87.9%, 801 homes
- Route R073 — Est. homes built 2010 or later 87.5%, 848 homes
- Route R057 — Est. homes built 2010 or later 85.3%, 652 homes
Select these 5 routes on the route map
Most businesses
For B2B offers: office supplies, cleaning, IT, catering and commercial services.
- Route R068 — USPS business mailboxes 173, 554 homes
- Route C036 — USPS business mailboxes 169, 1,309 homes
- Route R015 — USPS business mailboxes 70, 1,035 homes
- Route R066 — USPS business mailboxes 69, 1,073 homes
- Route R024 — USPS business mailboxes 56, 819 homes
Select these 5 routes on the route map
Every carrier route in 78665
| Route | Type | Homes | Businesses | Est. median income | Est. owners | Est. families with kids | Est. moved in past year |
|---|---|---|---|---|---|---|---|
| C036 | City | 1,309 | 169 | $64,722 | 0.6% | 16.6% | 46.3% |
| R006 | Rural | 1,490 | 5 | $115,611 | 66.6% | 37.8% | 28.2% |
| R011 | Rural | 679 | 1 | $139,453 | 85.2% | 45.2% | 20.3% |
| R013 | Rural | 1,146 | 5 | $50,681 | 32.9% | 13.1% | 30.5% |
| R015 | Rural | 1,035 | 70 | $74,271 | 39.5% | 24.8% | 23.3% |
| R020 | Rural | 1,121 | 3 | $97,447 | 66.6% | 43.0% | 24.6% |
| R022 | Rural | 680 | 0 | $192,863 | 90.4% | 54.9% | 13.7% |
| R024 | Rural | 819 | 56 | $84,999 | 54.9% | 24.2% | 21.6% |
| R025 | Rural | 773 | 0 | $181,968 | 85.3% | 66.7% | 19.7% |
| R028 | Rural | 795 | 34 | $121,634 | 65.0% | 49.8% | 29.3% |
| R029 | Rural | 835 | 32 | $131,396 | 75.1% | 39.9% | 8.8% |
| R030 | Rural | 787 | 4 | $137,265 | 77.3% | 46.0% | 9.6% |
| R037 | Rural | 666 | 3 | $160,962 | 84.7% | 53.1% | 19.4% |
| R042 | Rural | 1,325 | 34 | $74,531 | 16.9% | 27.0% | 42.2% |
| R047 | Rural | 823 | 10 | $147,650 | 73.6% | 48.6% | 20.4% |
| R049 | Rural | 879 | 1 | $162,803 | 91.4% | 58.0% | 16.1% |
| R050 | Rural | 1,058 | 39 | $82,563 | 26.9% | 32.4% | 35.0% |
| R051 | Rural | 1,055 | 0 | $126,868 | 75.2% | 46.9% | 19.4% |
| R052 | Rural | 707 | 27 | $118,956 | 57.1% | 36.3% | 19.9% |
| R053 | Rural | 825 | 1 | $200,000+ | 86.0% | 72.7% | 7.6% |
| R057 | Rural | 652 | 0 | $149,899 | 81.8% | 57.2% | 19.3% |
| R059 | Rural | 1,234 | 18 | $108,268 | 59.8% | 32.4% | 25.1% |
| R060 | Rural | 974 | 0 | $141,841 | 69.6% | 46.2% | 24.0% |
| R061 | Rural | 841 | 3 | $95,312 | 60.5% | 32.0% | 19.7% |
| R063 | Rural | 801 | 31 | $149,152 | 82.0% | 54.3% | 22.1% |
| R064 | Rural | 827 | 1 | $123,986 | 55.4% | 34.5% | 19.6% |
| R065 | Rural | 747 | 9 | $155,053 | 74.9% | 53.1% | 14.5% |
| R066 | Rural | 1,073 | 69 | $82,433 | 53.5% | 40.7% | 13.4% |
| R068 | Rural | 554 | 173 | $141,027 | 79.9% | 45.7% | 10.7% |
| R070 | Rural | 1,180 | 5 | $155,191 | 82.2% | 48.7% | 12.4% |
| R073 | Rural | 848 | 3 | $125,362 | 78.3% | 43.0% | 23.2% |
| R075 | Rural | 1,433 | 12 | $139,237 | 74.4% | 44.3% | 17.5% |
| R076 | Rural | 665 | 56 | $112,953 | 57.7% | 38.4% | 19.6% |
Income, owners, families and movers are estimates for each route (how we estimate them); mailbox counts are current USPS figures. Open 78665 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
- 78664 — Round Rock city, TX (3.1 mi)
- 78681 — Round Rock city, TX (4.8 mi)
- 78634 — Hutto city, TX (5.5 mi)
- 78728 — Austin city, TX (7.2 mi)
- 78626 — Georgetown city, TX (7.6 mi)
- 78660 — Pflugerville city, TX (7.9 mi)
- 78717 — Austin city, TX (8.1 mi)
- 78674 — Weir city, TX (8.7 mi)
Areas that include 78665
- Round Rock, TX ZIP codes — 3 ZIP codes
- Williamson County ZIP codes — 24 ZIP codes
- Austin ZIP code map — 89 ZIP codes
- Texas ZIP code data
Where it ranks
- No. 22 of 83: highest median household income in the Austin area
- No. 13 of 83: highest share of households with children in the Austin area
- No. 10 of 83: highest share of residents who moved in during the past year in the Austin area
- No. 15 of 81: fastest population growth in the Austin area
- No. 7 of 22: highest median household income in Williamson County
- No. 6 of 22: highest share of households with children in Williamson County
- No. 1 of 22: highest share of residents who moved in during the past year in Williamson County
- No. 7 of 21: fastest population growth in Williamson County
Mail every home in 78665
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) 78665, which approximates the USPS ZIP code area. Census figures: American Community Survey 5-year estimates, 2020–2024.
Frequently asked questions
- What city is 78665 in?
- 78665 is a Round Rock, TX mailing address. By land area, 61% lies inside Round Rock; the rest is outside any Census-defined city or community.
- What county is 78665 in?
- 78665 is in Williamson County.
- What is the population of 78665?
- About 66,171 people (±3,343), according to the Census Bureau's American Community Survey 5-year estimates for 2020–2024. The 2020 Census counted 61,577.
- What is the median household income in 78665?
- $122,680 (±$7,223), 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 78665?
- 33 USPS carrier routes with 30,636 residential and 874 business mailboxes (31,509 in all), from the route data stored by EDDM2GO. An EDDM mailing can target any combination of these routes.
- What ZIP codes are near 78665?
- The closest, measured center to center: 78664 (3.1 mi, Round Rock), 78681 (4.8 mi, Round Rock), 78634 (5.5 mi, Hutto), 78728 (7.2 mi, Austin), 78626 (7.6 mi, Georgetown) and 78660 (7.9 mi, Pflugerville).
This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.