Get API Key →
US ZIP Code Profile

ZIP Code 78642
Liberty Hill, Texas

ZIP code 78642 is in Liberty Hill, located in Williamson County, Texas, within the Austin-Round Rock metro area. Its 2020 Census population was 20,385. The estimated median adjusted gross income per tax return is $89,438, and about 19% of filers report $200,000 or more.

2020 Population
20,385
Census ZCTA
County
Williamson
FIPS 48491
Median income (est.)
$89,438
IRS SOI 2022
Land Area
100.129 mi²
+ 0.445 mi² water

01Location & Geography

Authoritative geographic identifiers from the U.S. Census Bureau, ANSI, and FIPS standards.

Primary CityLiberty Hill, TX
CountyWilliamson County (FIPS 48491)
StateTexas (FIPS 48)
Metro Area (MSA)Austin-Round Rock, TX Metro Area (12420)
Census Region / DivisionSouth Region · West South Central Division
Coordinates30.69088, -97.94143
Land / Water Area100.129 mi² land · 0.445 mi² water

02Income & Economics

Distribution of the 13,250 individual tax returns filed in 78642 by adjusted gross income bracket (IRS SOI, 2022).

< $25K
17.9%
$25K–$50K
14.8%
$50K–$75K
11.7%
$75K–$100K
9.7%
$100K–$200K
27.3%
$200K+
18.6%
The $200,000+ bracket accounts for 55% of 78642's total adjusted gross income, from 19% of returns — a concentration that drives the gap between the median ($89,438) and the average.
Estimated median = median adjusted gross income per tax return, interpolated from IRS SOI brackets. Differs from U.S. Census household income.

03Income Over Time

Year-over-year change in 78642's IRS income metrics, 2020–2022.

Median income (2021→2022)
$89,438
▲ 11.7%
Filers earning $200K+
18.6%
▲ 2.6 pt
Total filers
13,250
▲ 12.6%
GET /zipc/v2/zipcodes/78642/soi?year=… $71K 2020 $80K 2021 $89K 2022
Median = adjusted gross income per return, interpolated from IRS SOI brackets. Figures are nominal (not inflation-adjusted).

04Population Trend

Decennial U.S. Census population for the 78642 ZCTA.

2000
6,061
 
2010
9,467
▲ +56.2%
2020
20,385
▲ +115.3%

05USPS Postal Details

Delivery and facility attributes from the monthly USPS dataset.

ZIP ClassificationNon-Unique Zip
Facility TypePost Office
Carrier Route SortD
USPS Finance Number485145
City AliasesLiberty Hill

06Frequently Asked Questions

What county is ZIP code 78642 in?

ZIP code 78642 is in Williamson County, Texas (county FIPS code 48491).

What city is ZIP code 78642?

The primary USPS city for 78642 is Liberty Hill, TX.

What metro area (MSA) is 78642 in?

78642 is part of the Austin-Round Rock, TX Metro Area (MSA code 12420).

What is the population of ZIP code 78642?

The 2020 Census population of 78642 was 20,385 residents.

What is the median income in ZIP code 78642?

Based on IRS Statistics of Income data, the estimated median adjusted gross income per tax return in 78642 is about $89,438, with around 19% of filers reporting $200,000 or more. Note that adjusted gross income is a tax measure and differs from U.S. Census household income.