Home > TX > Williamson County > Round Rock > Zip 78664

Zip Code 78664 — Round Rock, TX

78664 is a ZIP Code associated with Round Rock, TX, located within Williamson. The postal region supports an estimated population of 62,060 residents across Data Pending housing units, with a population density of 1,442.4 people per square mile.
WorldPlaceData database updated: October 2026

📍 View location on OpenStreetMap (30.504610, -97.645830)

Data MetricLocal Statistic
Postal / Zip Code78664
Primary CityRound Rock
State / ProvinceTX
CountyWilliamson
Total Population62,060
Median Household IncomeData Pending
Total Housing UnitsData Pending
Population Density1,442.4 people/sq mi
TimezoneAmerica/Chicago

How 78664 Compares

MetricZIP 78664Williamson CountyTX State Average
Population62,060591,18730,188,035
Median IncomeData PendingN/AN/A
Population Density1,442.4 /sq mi----

Nearby ZIP Codes

ZIP CodeCityDistancePopulationMedian Income
Zip 78665Round Rock3.2 mi66,171N/A
Zip 78728Austin4.3 mi26,777N/A
Zip 78681Round Rock4.9 mi56,691N/A
Zip 78660Pflugerville5.2 mi124,834N/A
Zip 78717Austin6.5 mi37,262N/A

Data Sources & Methodology: Geographic coordinates and ZIP Code assignments are derived from underlying geographic and postal datasets. Note that ZIP Codes are USPS postal delivery areas, while Census ZCTAs are statistical approximation areas. Read full methodology →