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US ZIP Code Profile

ZIP Code 78655
Martindale, Texas

ZIP code 78655 is in Martindale, located in Caldwell County, Texas, within the Austin-Round Rock metro area. Its 2020 Census population was 2,910. The estimated median adjusted gross income per tax return is $44,257, and about 5% of filers report $200,000 or more.

2020 Population
2,910
Census ZCTA
County
Caldwell
FIPS 48055
Median income (est.)
$44,257
IRS SOI 2022
Land Area
35.641 mi²
+ 0.22 mi² water

01Location & Geography

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

Primary CityMartindale, 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
Coordinates29.816063, -97.83505
Land / Water Area35.641 mi² land · 0.22 mi² water

02Income & Economics

Distribution of the 1,350 individual tax returns filed in 78655 by adjusted gross income bracket (IRS SOI, 2022).

< $25K
28.9%
$25K–$50K
27.4%
$50K–$75K
16.3%
$75K–$100K
8.9%
$100K–$200K
13.3%
$200K+
5.2%
The $200,000+ bracket accounts for 29% of 78655's total adjusted gross income, from 5% of returns — a concentration that drives the gap between the median ($44,257) 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 78655's IRS income metrics, 2020–2022.

Median income (2021→2022)
$44,257
▲ 7.4%
Filers earning $200K+
5.2%
▼ 0.0 pt
Total filers
1,350
▲ 0.7%
GET /zipc/v2/zipcodes/78655/soi?year=… $40K 2020 $41K 2021 $44K 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 78655 ZCTA.

2000
2,310
 
2010
2,739
▲ +18.6%
2020
2,910
▲ +6.2%

05USPS Postal Details

Delivery and facility attributes from the monthly USPS dataset.

ZIP ClassificationNon-Unique Zip
Facility TypePost Office
Carrier Route SortC
USPS Finance Number485680
City AliasesMartindale

06Frequently Asked Questions

What county is ZIP code 78655 in?

ZIP code 78655 is in Caldwell County, Texas (county FIPS code 48055).

What city is ZIP code 78655?

The primary USPS city for 78655 is Martindale, TX.

What metro area (MSA) is 78655 in?

78655 is part of the Austin-Round Rock, TX Metro Area (MSA code 12420).

What is the population of ZIP code 78655?

The 2020 Census population of 78655 was 2,910 residents.

What is the median income in ZIP code 78655?

Based on IRS Statistics of Income data, the estimated median adjusted gross income per tax return in 78655 is about $44,257, with around 5% of filers reporting $200,000 or more. Note that adjusted gross income is a tax measure and differs from U.S. Census household income.