Williamson County, Texas

County seat: Georgetown · Population 752,827 (2025) · 1,116 sq mi

Williamson County is the 12th most populous of Texas's 254 counties, with 752,827 people (2025 estimate). Its county seat is Georgetown. It is part of the Capital region, one of the 12 Texas Comptroller economic regions. The map shows its 17 cities and towns and the 6 neighboring counties.

Map of Williamson County, Texas with cities, towns and the county boundary
Williamson County, Texas with its cities and towns, unincorporated communities (CDPs) and neighboring counties. Boundaries: U.S. Census Bureau, 2025. Free to use with attribution (CC BY 4.0).
Download PDF (Letter) 158 KBPNG image 87 KBTexas county map

Williamson County facts

County seat
Georgetown
Population (2025 estimate)
752,827 +23.6% since 2020
Land area
1,116 sq mi 47th largest of 254
Water area
16 sq mi
Population density
675 per sq mi
Established
1848
Named after
Robert McAlpin Williamson Texas judge and ranger (1804–1859)
Largest city
Round Rock 139,317 in the county
Median household income
$111,340
Cities and towns
17 plus 4 CDPs
ZIP codes
27
Time zone
Central
FIPS code
48491

Cities and towns in Williamson County

Williamson County has 17 incorporated cities, towns and villages. Populations count the people living inside Williamson County; cities that cross a county line also list the other counties.

NameTypePopulation 2025Also in
Round RockCity139,317Travis County
Georgetown (county seat)City106,907
LeanderCity78,611Travis County
Cedar ParkCity72,327Travis County
AustinCity72,071Bastrop, Hays and Travis counties
HuttoCity46,048
TaylorCity18,402
Liberty HillCity13,317
JarrellCity5,870
FlorenceCity1,245
GrangerCity1,228
BartlettCity982Bell County
ThrallCity886
WeirCity792
CouplandCity305
PflugervilleCity195Travis County
ThorndaleCity1Milam County

Unincorporated communities (CDPs)

Census-designated places are communities without their own city government; the county provides their services.

CommunityPopulationAlso in
Brushy Creek19,576
Sonterra10,563
Santa Rita Ranch6,586
Serenada1,444

ZIP codes in Williamson County

27 ZIP codes reach into Williamson County. ZIP codes ignore county lines, so some also cover a neighboring county.

Population of Williamson County, 2020–2025

Williamson County grew by 143,768 people (+23.6%) between April 2020 and July 2025: 21,338 more births than deaths and a net gain of 122,783 people from migration.

Year (July 1)Population
2020615,611
2021644,790
2022674,478
2023701,798
2024729,013
2025752,827

Neighboring counties

Printable Williamson County map

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Sources

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