Get API Key →
US ZIP Code Profile

ZIP Code 78663
Round Mountain, Texas

ZIP code 78663 is in Round Mountain, located in Blanco County, Texas. Its 2020 Census population was 815. The estimated median adjusted gross income per tax return is $66,071, and about 17% of filers report $200,000 or more.

2020 Population
815
Census ZCTA
County
Blanco
FIPS 48031
Median income (est.)
$66,071
IRS SOI 2022
Land Area
123.136 mi²
+ 0.693 mi² water

01Location & Geography

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

Primary CityRound Mountain, TX
CountyBlanco County (FIPS 48031)
StateTexas (FIPS 48)
Census Region / DivisionSouth Region · West South Central Division
Coordinates30.402262, -98.359566
Land / Water Area123.136 mi² land · 0.693 mi² water

02Income & Economics

Distribution of the 470 individual tax returns filed in 78663 by adjusted gross income bracket (IRS SOI, 2022).

< $25K
21.3%
$25K–$50K
19.1%
$50K–$75K
14.9%
$75K–$100K
8.5%
$100K–$200K
19.1%
$200K+
17.0%
The $200,000+ bracket accounts for 67% of 78663's total adjusted gross income, from 17% of returns — a concentration that drives the gap between the median ($66,071) 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 78663's IRS income metrics, 2020–2022.

Median income (2021→2022)
$66,071
▼ 2.1%
Filers earning $200K+
17.0%
▲ 1.5 pt
Total filers
470
▲ 4.4%
GET /zipc/v2/zipcodes/78663/soi?year=… $55K 2020 $68K 2021 $66K 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 78663 ZCTA.

2000
351
 
2010
746
▲ +112.5%
2020
815
▲ +9.2%

05USPS Postal Details

Delivery and facility attributes from the monthly USPS dataset.

ZIP ClassificationNon-Unique Zip
Facility TypePost Office
Carrier Route SortC
USPS Finance Number487800
City AliasesRound Mountain, Cypress Mill, Round Mtn

06Frequently Asked Questions

What county is ZIP code 78663 in?

ZIP code 78663 is in Blanco County, Texas (county FIPS code 48031).

What city is ZIP code 78663?

The primary USPS city for 78663 is Round Mountain, TX.

What is the population of ZIP code 78663?

The 2020 Census population of 78663 was 815 residents.

What is the median income in ZIP code 78663?

Based on IRS Statistics of Income data, the estimated median adjusted gross income per tax return in 78663 is about $66,071, with around 17% of filers reporting $200,000 or more. Note that adjusted gross income is a tax measure and differs from U.S. Census household income.