Data Last Updated: April 1, 2025

Williamson County, TX ZIP Codes

ZIP Codes: Shows how many general ZIP Codes, PO Boxes, Unique (Business), and Multi County ZIP Codes are associated with Williamson, TX.	35 ZIP Codes (18 General, 8 PO Box, 1 Unique, & 8 Multi County) [More Details]
Area Codes: The Telephone Area Codes that are associated with Williamson, TX. Area Codes are used in the North American Numbering Plan (NANP) to facilitate phone routing. There are approximately 350 area codes in use in the United States.	254, 512, 737
Timezone: Time zone designation within the U.S. Please note that not all areas in the U.S. observe daylight saving time which can affect actual local time for this city. There are 7 standard time zones which are, from west to east: Hawaii-Aleutian, Alaska, Pacific, Mountain, Central, Eastern, Atlantic. Also included in U.S. Territories are Samoa, Guam and Palau.	Central
Local Time: The current local time for each timezone. If more than 1 time zone for this area, all local times will be shown. Counties can cross timezones, so more than 1 may be shown.	12:00:00 AM
Population: The population of Williamson, TX from the U.S. Census 2020. Included are U.S. Citizens, permanent residents, temporary migrants, and undocumented individuals. The total population represents people who live in the city, not just those present while the Census was being completed.	609,017 [More Details]
FIPS: FIPS stands for Federal Information Processing Standards, which are a set of publicly announced standards for computer systems. A county FIPS code is a unique numeric identifier for a county in the United States, assigned by the National Institute of Standards and Technology (NIST). County FIPS codes have five digits, with the first two digits identifying the state and the last 3 indicating the county.	48491
CBSA: A Core Based Statistical Area (CBSA) is the recognized term for a region that functions around an urban core with a population of at least 10,000 people, according to the standards set by the Office of Management and Budget (OMB) in 2000. A CBSA is divided into two subsets: Metro and Micro, and these classifications are determined by population density. A Micro area is identified by a population ranging between 10,000 to 50,000, while a Metro area is defined as having a population that exceeds 50,000.	Austin-Round Rock-San Marcos, TX
Land Area: The approximate amount of land area covered by Williamson, TX in square miles. The Land Area provided by the Census Bureau is based on geographic boundaries that include the mainland, islands, inland, coastal, Great Lakes, and territorial waters associated with each city.	1,116 square miles
Water Area: The approximate amount of water area covered by Williamson, TX in square miles. Calculations by the Census Bureau for Water Area take into account inland bodies of water, coastal regions, Great Lakes, and territorial sea waters. This encompasses features such as lakes, reservoirs, rivers, and coastal water bodies.	16 square miles
Coordinates: The latitude/longitude centroid coordinates for Williamson County, TX.	-97.600403, 30.647526
Quick Link: Copy the direct link to the Williamson, TXCounty page and use anywhere you like!	https://www.zip-codes.com/county/tx-williamson.asp

Williamson, TX ZIP Code Boundaries

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Williamson County, TX Covers 35 ZIP Codes

ZIP Code	Classification	City	Population	% of Population
ZIP Code 76511 *	General	Bartlett	2,451	--
ZIP Code 76527	General	Florence	4,688	0.77%
ZIP Code 76530	General	Granger	2,654	0.44%
ZIP Code 76537	General	Jarrell	10,943	1.80%
ZIP Code 76573	P.O. Box	Schwertner	26	0.00%
ZIP Code 76574	General	Taylor	19,366	3.18%
ZIP Code 76577 *	General	Thorndale	3,262	--
ZIP Code 76578	General	Thrall	1,817	0.30%
ZIP Code 78613	General	Cedar Park	89,279	14.66%
ZIP Code 78615	General	Coupland	1,694	0.28%
ZIP Code 78621 *	General	Elgin	27,275	--
ZIP Code 78626	General	Georgetown	39,935	6.56%
ZIP Code 78627	P.O. Box	Georgetown	0	0.00%
ZIP Code 78628	General	Georgetown	40,378	6.63%
ZIP Code 78630	P.O. Box	Cedar Park	0	0.00%
ZIP Code 78633	General	Georgetown	27,736	4.55%
ZIP Code 78634	General	Hutto	37,951	6.23%
ZIP Code 78641	General	Leander	83,426	13.70%
ZIP Code 78642	General	Liberty Hill	20,385	3.35%
ZIP Code 78646	P.O. Box	Leander	0	0.00%
ZIP Code 78660 *	General	Pflugerville	110,955	--
ZIP Code 78664	General	Round Rock	60,287	9.90%
ZIP Code 78665	General	Round Rock	61,577	10.11%
ZIP Code 78673	P.O. Box	Walburg	0	0.00%
ZIP Code 78674	P.O. Box	Weir	287	0.05%
ZIP Code 78680	P.O. Box	Round Rock	0	0.00%
ZIP Code 78681	General	Round Rock	57,503	9.44%
ZIP Code 78682	Unique	Round Rock	0	0.00%
ZIP Code 78683	P.O. Box	Round Rock	0	0.00%
ZIP Code 78717	General	Austin	36,987	6.07%
ZIP Code 78727 *	General	Austin	29,928	--
ZIP Code 78728 *	General	Austin	25,555	--
ZIP Code 78729	General	Austin	31,829	5.23%
ZIP Code 78750 *	General	Austin	28,348	--
ZIP Code 78759 *	General	Austin	42,333	--

* Indicates a Multi County ZIP Code. These ZIP Codes partially cross over into Williamson, TX, but will mostly cover area in a different County. Not included in % of Population calculations.

Important Williamson, TX Information

Williamson County, TX Covers 35 ZIP Codes. This includes 18 General ZIP Codes, 8 PO Box ZIP Codes, and 1 Unique (reserved for Business and Volume Mail Receivers). There are also 8 Multi County ZIP Codes. These records are assigned a different primary county, but they partially cover area in Williamson County.

The population for Williamson County is 609,017, according to the U.S. Census. Population Density is 545.71 persons per square mile. With 237,680 Housing Units, the Average Household Size is 2.69 persons. There are 224,506 Family Households with an Average Family Size of 2.75 persons. 8.57% of the population is without Health Insurance. The 67.92% Employment Rate is 8.12% above the national average of 59.8%.435,869 people aged 25+ have some educational achievement, with 47.40% (or 206,612 people) having attained a Bachelor's Degree or higher.More Demographics are available below.

There are 3 area codes serving this area including254, 512 and 737. Williamson is also located in the Central timezone and the current local time is shown above.

Williamson is part of the Austin-Round Rock-San Marcos, TX Core Based Statistical Area (CBSA). Its CBSA Code is 12420.It is classified as a metro area, which means the combined population is 50,000 or more (at its core).

CBSAs are defined by the OMB as geographic areas that have at least one core with a population of 10,000 or more (for a micro area) and adjacent territory with a high degree of social and economic integration. CBSA codes are commonly used to accurately file Medicare claims and to verify applicable incentives using a patient's ZIP Code.

ZIP Codes in Williamson, TX have 300,844 Residential mailboxes and 12,907 Business mailboxes.There are 14,173 businesses with a total of 184,222 employees. That is an average of 13.0 employees per business. Annual payroll for these businesses is $11,576,865,000. Other Demographics

Williamson County Demographic Profile

Population & People

Total Population

609,017

Income

Median Household Income

$108,309

Housing

Total Housing Units

237,680

Health

Without Healthcare Coverage

8.57%

Business & Economy

Total Businesses

14,173

Families

Total Households

224,506

Employment

Employment Rate

67.92%

Education

Bachelor's Degree or Higher

47.40%

Total Population: Total number of people from the 2020 U.S. Census for Williamson, TX. This reflects the exact count of this area at that point in time, not future estimates, regardless of citizenship or immigration status. It is intended to count all persons living within the geographic area, not just those present on the day of the census.	609,017
Current Population Estimate: This field gives the estimated household population for All ZIP Codes in Williamson, TX. This is derived from known delivery information, household occupancy rates, household size, and more to come up with an accurate estimation for the current population. IMPORTANT: This does not include population totals for persons in nursing homes, correctional facilities, or other institutions. This is an estimation of the household population based on US Postal Service delivery information.	824,606
Total Households: Total number of Households from the 2020 U.S. Census for Williamson, TX. A Household includes everyone living in a residential housing unit. This includes families, roommates in a single residence, or a person living alone.	224,506
Total Housing Units: The total number of Housing Units is the number of occupied units + the number of vacant units. Ownership is defined by whether the unit is occupied by an owner or by a tenant. Owner occupancy means that the owner lives in the unit. This value comes from the 2020 U.S. Census and is not a projection or estimate.	237,680
Average Household Size: The Average Household Size, is obtained by dividing the number of people in Households (excluding those in group quarters, nursing home, prisons, and dorm rooms) by the number of Households. A Household includes everyone living in a residential unit. Those who do not live in a household are classified as living in group accommodation. This value is an estimate from the U.S. Census ACS (American Community Survey) and is updated yearly.	2.69
Average Family Size: Average Family Size is calculated by dividing the number of people in a Family Household by the number of Family Households. The U.S. Census Bureau defines family households as households consisting of two or more individuals who are related by birth, marriage, or adoption. They also may include other unrelated people. Non-family households consist of people who live alone or who share their residence with unrelated individuals. The Average Family Size only looks at the households classified as Family Households. This value is an estimate from the U.S. Census ACS (American Community Survey) and is updated yearly.	2.75

Other Williamson Demographics

# Residential Mailboxes: The number of active residential delivery mailboxes and centralized units. This excludes PO Boxes and all other contract box types.	300,844
# Business Mailboxes: The number of active business delivery mailboxes and centralized units. This excludes PO Boxes and all other contract box types.	12,907
Total Delivery Receptacles: The total number of delivery receptacles. This includes curb side mailboxes, centralized units, PO Boxes, NDCBU, and contract boxes. This count is for Residential and Business combined.	437,519
Single Family Delivery Units: Total count of single family mail delivery receptacles; generally analogous to homes.	51,615
Multi Family Delivery Units: Total count of multifamily mail delivery receptacles; generally analogous to apartments.	52,005

# of Businesses: The total number of Business Establishments. Data taken from Business Census 2023.	14,173
1st Quarter Payroll: The total payroll for the first quarter. Data taken from Business Census 2023.	$2,971,863,000
Annual Payroll: The total annual payroll . Data taken from Business Census 2023.	$11,576,865,000
# of Employees: The total number of employees for all ZIP Codes in this City. Data taken from Business Census 2023.	184,222

Sum of all ZIP Codes assigned Williamson, TX as their primary County.

References

U.S. Postal Service [Last Updated: 4/1/2025], https://www.usps.com
ZIP-Codes.com Internal Data Creation [Last Updated: 4/1/2025], https://www.zip-codes.com
U.S. Geological Survey [Updated as needed], https://www.usgs.gov
U.S. Census [Updated Yearly], https://www.census.gov
U.S. Census 2020 [Decennial] [Last Updated: 5/25/2023], https://www.census.gov