Zip Code 78664
Round Rock, Texas — Williamson County
📍 ZIP code 78664 is in Round Rock, Williamson County, Texas.
ZIP code 78664 is located in Round Rock, Williamson County, Texas. It is a zip code in the Central (CST/CDT) Time Zone with an estimated population of 62,272. The area code for ZIP code 78664 is 512.
Quick Answer
Zip code 78664 is in Round Rock, Texas (Williamson County). It has a population of 62,272, median household income of $85,919, and median home value of $317,400.
Population
62,272
Income
$85,919
Home Value
$317,400
Climate
96°F / 38°F
About Zip Code 78664
Zip code 78664 is located in Round Rock, Texas, within Williamson County. Home to approximately 62,272 residents, this area sits at an elevation of 693 ft and falls within the Central (CST/CDT) timezone. The local area code is 512.
The median household income is $85,919 per year, which is above the national median of $70,784. Homes in this zip code have a median value of $317,400, and the cost of living index is 105 (5% above the national average of 100).
Summers average a high of 96°F while winters drop to 38°F. The area receives about 37 in of rain annually. The zip code covers 16.6 square miles of land area and 0.1 square miles of water.
Key Statistics
62,272
$85,919
$317,400
Central (CST/CDT)
512
693 ft
16.6 sq mi
34.8
24,259
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Compare With Nearby Zip Codes
| Metric | 78664 | 78728 | 78681 | 78660 | 78717 | 78727 |
|---|---|---|---|---|---|---|
| City | Round Rock, TX | Austin, TX | Round Rock, TX | Pflugerville, TX | Austin, TX | Austin, TX |
| Population | 62,272 | 26,776 | 58,531 | 118,437 | 36,085 | 30,894 |
| Median Income | $85,919 | $74,048 | $136,215 | $109,522 | $140,483 | $107,194 |
| Home Value | $317,400 | $392,600 | $460,000 | $369,300 | $599,200 | $483,200 |
| Cost of Living | 105 | 113 | 156 | 128 | 187 | 145 |
| Median Age | 34.8 | 33.9 | 39 | 35.6 | 36.3 | 35 |
Cost of Living
100 = National Average. Round Rock's cost of living is 5% above the national average.
vs. State Avg
Above
Affordability
Moderate
Income-to-Home
3.7x
Demographics
Zip code 78664 has a population of 62,272 people with a median age of 34.8. There are 24,259 housing units in this area.
Racial & Ethnic Composition
Source: U.S. Census Bureau American Community Survey estimates.
Population History
Round Rock (78664) population trend from 2010 to 2024
↑ 26.5%Source: U.S. Census Bureau estimates and American Community Survey data.
Climate & Weather
96°F
38°F
37 in
0 in
Round Rock experiences hot summers with average highs around 96°F. Winters are mild with lows averaging 38°F. The area receives virtually no snowfall.
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Housing & Economy
Median Home Value
$317,400
Median Household Income
$85,919
With 24,259 housing units across 16.6 square miles, 78664 has a housing density of 1,461 units per square mile. The home price-to-income ratio is 3.7x.
Location & Geography
Latitude
30.5054°
Longitude
-97.6473°
Land Area
16.6 sq mi
Water Area
0.1 sq mi
Nearby Zip Codes
Zip codes closest to 78664 (Round Rock, TX) with distances:
All Zip Codes in Round Rock, TX
Other zip codes serving Round Rock:
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ZIP Codes with Similar Income Nationwide
The five U.S. ZIP codes whose median household income is closest to 78664's $85,919. A way to compare Round Rock to economically similar communities elsewhere in the country.
Computed from U.S. Census Bureau ACS 5-Year Estimates by the Zip Code Near Me Data Team.
ZIP Codes with Similar Demographics
The five U.S. ZIP codes whose racial and ethnic composition most closely matches 78664 (Round Rock, TX). Similarity is measured by cosine distance on the five-category ACS demographic vector.
Computed from U.S. Census Bureau ACS 5-Year Estimates by the Zip Code Near Me Data Team.
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People Also Ask
What zip code is Round Rock, Texas?
Round Rock, Texas uses zip code 78664 along with 1 other zip codes.
What county is zip code 78664 in?
Zip code 78664 is located in Williamson County, Texas.
What is the population of zip code 78664?
The population of zip code 78664 is 62,272 with a median age of 34.8.
Is 78664 in Round Rock, Texas?
Yes, zip code 78664 is in Round Rock, Williamson County, Texas. The area code is 512.
Frequently Asked Questions
What city is zip code 78664 in?
Zip code 78664 is in Round Rock, Texas. It is part of Williamson County and uses the Central (CST/CDT) timezone.
What is zip code 78664?
Zip code 78664 is a U.S. postal code in Round Rock, Texas (Williamson County). It has a population of 62,272 and covers 16.6 square miles.
What is the population of zip code 78664?
The population of zip code 78664 (Round Rock, TX) is 62,272 with a median age of 34.8. There are approximately 24,259 housing units in this area.
What is the median income in zip code 78664?
The median household income in zip code 78664 (Round Rock, TX) is $85,919 per year. The cost of living index is 105 (100 = national average).
What is the average home price in zip code 78664?
The median home value in zip code 78664 (Round Rock, TX) is $317,400. The cost of living index is 105 compared to the national average of 100.
What county is zip code 78664 in?
Zip code 78664 is located in Williamson County, Texas. The primary city is Round Rock.
What is the area code for zip code 78664?
Zip code 78664 in Round Rock, TX uses area code 512. It is located in the Central (CST/CDT) timezone.
Is zip code 78664 a good place to live?
Zip code 78664 (Round Rock, TX) has a cost of living index of 105 (100 = national average), a median household income of $85,919, and median home values of $317,400. The median age is 34.8. Visit the full page for demographics, climate, and nearby zip code comparisons.
What is the cost of living in zip code 78664?
The cost of living index for zip code 78664 (Round Rock, TX) is 105, where 100 represents the national average. This area is above the national average. Median home value: $317,400.
What schools serve zip code 78664?
Zip code 78664 in Round Rock, Texas is served by the local school district of Williamson County. For specific school information, check your state's department of education or GreatSchools.org.
All demographic data on this page is sourced from the U.S. Census Bureau American Community Survey (ACS) 5-Year Estimates. ZIP code boundary and delivery data is sourced from the United States Postal Service (USPS). Data is updated periodically and may not reflect the most current figures. Census Bureau ZIP Code Tabulation Areas (ZCTAs) may differ slightly from USPS ZIP code boundaries.
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Data Sources
- Population, income, housing, age, and demographics
- U.S. Census Bureau, American Community Survey 5-Year Estimates, 2019-2023 vintage.
- ZIP to city and county mapping
- USPS and HUD-USPS ZIP-County Crosswalk.
- Time zones and area codes
- IANA tz database and NANPA.
- Elevation
- U.S. Geological Survey National Elevation Dataset (NED), via the USGS Elevation Point Query Service. Mapped to each ZCTA centroid coordinates. Last refreshed 2026-05-19.
- Last refreshed
- 2026-05-18.