ZIP Codes of Mahaska County, IA

Population & People
Population & People
Total Population
20,715
Household Income
Household Income
Median Income
$68,720
Housing
Housing
Total Housing Units
9,151
Business & Economy
Business & Economy
Total Businesses
515
Employment
Employment
Employment Rate
62.23%
Education
Education
Bachelor's Degree+
24.45%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 9 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:9 ZIP Codes (8 Standard, 1 PO Box, 0 Unique) [See All]
Area Code:641
Timezone:Central (GMT -06:00)
Local Time:2:11:53 PM
Population:20,715 [See All]
FIPS:19123
CBSA:Oskaloosa, IA
Land Area:472 sq mi
Water Area:2 sq mi
Coordinates:41.3155, -92.5782
Quick Link:
https://www.zip-codes.com/county/ia-mahaska.asp
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Extreme geographic sprawl
The largest ZIP spans 242× the smallest by area — 158.7 sq mi down to 0.66.

Standout ZIPs in this County


Most Populous
Oskaloosa · 14,585 people
70.4% of county total
Highest Income
Leighton · $86,023 median
1.3× county average
Largest Land Area
Oskaloosa · 158.7 sq mi
Spans the most ground
Fastest Growth
Oskaloosa · -3.0% (10-yr)
15,041 → 14,585 residents
Most Educated
Oskaloosa · 26.1% bachelor's+
2,531 of 9,691 adults 25+

Things worth knowing about Mahaska County


20,715 residents live across 9 ZIPs covering 472 sq mi, served by 9 distinct USPS-recognized cities.

Population moved from 20,968 to 20,715 from 2014 to 2024 — a -1.2% change. 4 ZIPs gained residents, 5 lost.

The county's wealthiest ZIP 50143 (Leighton, $86,023 median) and poorest ZIP 50027 (Barnes City, $52,976) are 19.8 miles apart — a 1.6× income gap across local geography.

Median home values vary 4.2× across this county — from $75,700 in 52534 (Beacon) to $314,600 in 50143 (Leighton).

Density varies 220× across the county — from 5 people/sq mi in 50027 (Barnes City) to 1,156 in 52595 (University Park).

Educational attainment ranges from 6.3% bachelor's+ in 50027 (Barnes City) to 35.8% in 50143 (Leighton) — the breadth of educational profiles across the area.

Within Iowa, this is the #32 most populous of 99 counties and ranks #76 for median household income .

Weighted by population, the typical household earns about $68,132 across the county — reflecting what a typical resident sees, not a simple ZIP average.

24.5% of adults age 25+ hold a bachelor's degree or higher (3,351 of 13,703 reporting).

8 Standard delivery, 1 PO Box only, 0 single-entity Unique ZIPs serve this county.

Stories about Mahaska County


Single-ZIP anchor

One ZIP holds the majority of this county's population — a sign of a county built around a single city or town.

Oskaloosa

All ZIP Codes in Mahaska County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
52577OskaloosaStandard14,585$66,084158.7-3.0%
50207New SharonStandard2,325$76,053140.7-3.2%
52561FremontStandard1,112$76,05839.221.8%
52586Rose HillStandard600$53,12544.463.9%
52595University ParkPO Box545$66,6670.510.8%
52543CedarStandard541$83,51122.0-0.4%
50143LeightonStandard538$86,02337.5-23.6%
52534BeaconStandard321$57,9860.753.6%
50027Barnes CityStandard148$52,97628.2-50.2%

Adjacent & Nearby Counties