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US ZIP Code Profile

ZIP Code 78644
Lockhart, Texas

ZIP code 78644 is in Lockhart, located in Caldwell County, Texas, within the Austin-Round Rock metro area. Its 2020 Census population was 20,813. The estimated median adjusted gross income per tax return is $43,345, and about 3% of filers report $200,000 or more.

2020 Population
20,813
Census ZCTA
County
Caldwell
FIPS 48055
Median income (est.)
$43,345
IRS SOI 2022
Land Area
186.63 mi²
+ 0.707 mi² water

01Location & Geography

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

Primary CityLockhart, TX
CountyCaldwell County (FIPS 48055)
StateTexas (FIPS 48)
Metro Area (MSA)Austin-Round Rock, TX Metro Area (12420)
Census Region / DivisionSouth Region · West South Central Division
Coordinates29.871643, -97.67682
Land / Water Area186.63 mi² land · 0.707 mi² water

02Income & Economics

Distribution of the 9,540 individual tax returns filed in 78644 by adjusted gross income bracket (IRS SOI, 2022).

< $25K
28.6%
$25K–$50K
29.1%
$50K–$75K
16.9%
$75K–$100K
9.6%
$100K–$200K
12.3%
$200K+
3.5%
The $200,000+ bracket accounts for 26% of 78644's total adjusted gross income, from 3% of returns — a concentration that drives the gap between the median ($43,345) 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 78644's IRS income metrics, 2020–2022.

Median income (2021→2022)
$43,345
▲ 7.9%
Filers earning $200K+
3.5%
▲ 0.5 pt
Total filers
9,540
▲ 4.0%
GET /zipc/v2/zipcodes/78644/soi?year=… $38K 2020 $40K 2021 $43K 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 78644 ZCTA.

2000
15,368
 
2010
17,081
▲ +11.1%
2020
20,813
▲ +21.8%

05USPS Postal Details

Delivery and facility attributes from the monthly USPS dataset.

ZIP ClassificationNon-Unique Zip
Facility TypePost Office
Carrier Route SortD
USPS Finance Number485240
City AliasesLockhart, Mendoza, Seawillow

06Frequently Asked Questions

What county is ZIP code 78644 in?

ZIP code 78644 is in Caldwell County, Texas (county FIPS code 48055).

What city is ZIP code 78644?

The primary USPS city for 78644 is Lockhart, TX.

What metro area (MSA) is 78644 in?

78644 is part of the Austin-Round Rock, TX Metro Area (MSA code 12420).

What is the population of ZIP code 78644?

The 2020 Census population of 78644 was 20,813 residents.

What is the median income in ZIP code 78644?

Based on IRS Statistics of Income data, the estimated median adjusted gross income per tax return in 78644 is about $43,345, with around 3% of filers reporting $200,000 or more. Note that adjusted gross income is a tax measure and differs from U.S. Census household income.