Find the last 4 digits (ZIP+4) for an address in 78664

ZIP 78664, Round Rock, TX is filled in. Just type the street address.

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ZIP Code 78664 – Round Rock, TX

Round Rock, Texas · Williamson County · Central time

ZIP code78664
CityRound Rock
StateTexas
CountyWilliamson CountyTravis County
Population62,060
Time zoneCentral · local time
ZIP typeStandard (has a Census ZCTA area)
Land area16.61 sq mi
Center (lat, long)30.5054, -97.6473

Area codes in this area

512737

These are the area codes that most often serve ZIP 78664 (including overlays). The exact area code depends on the phone number — landlines, mobiles and overlays can differ even on the same street.

Map

Nearby ZIP codes

78665 Round Rock · 3.1 mi78764 Austin · 4.2 mi78728 Austin · 4.3 mi78681 Round Rock · 4.8 mi78691 Pflugerville · 4.8 mi78660 Pflugerville · 5.5 mi78717 Austin · 6.4 mi78727 Austin · 6.7 mi

About ZIP 78664

ZIP code 78664 is assigned to Round Rock, Texas. It crosses 2 counties; most of its land is in Williamson County. Its Census area covers about 16.61 square miles of land. The closest neighboring ZIP is 78665 (Round Rock), about 3.1 miles away.

Every address in 78664 also has a 4-digit add-on code (ZIP+4) that points to a smaller delivery area. Use the box above to find it.

Sources: US Census Bureau (ZCTA, county relationship files), GeoNames (CC BY 4.0), NANPA via NumberResearch.org (CC BY 4.0). Map © OpenStreetMap contributors. ZIP areas are approximate. Population: U.S. Census Bureau, ACS 5-year estimates, 2024 (ZCTA). Data sources