ZIP Codes of Calhoun County, IA

Population & People
Population & People
Total Population
10,375
Household Income
Household Income
Median Income
$68,997
Housing
Housing
Total Housing Units
5,093
Business & Economy
Business & Economy
Total Businesses
290
Employment
Employment
Employment Rate
54.83%
Education
Education
Bachelor's Degree+
21.85%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 10 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:10 ZIP Codes (9 Standard, 1 PO Box, 0 Unique) [See All]
Area Codes:515 / 712
Timezone:Central (GMT -06:00)
Local Time:2:11:51 PM
Population:10,375 [See All]
FIPS:19025
Land Area:614 sq mi
Water Area:2 sq mi
Coordinates:42.4068, -94.6027
Quick Link:
https://www.zip-codes.com/county/ia-calhoun.asp
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Iowa's #71 most populous county
10,375 residents across 10 ZIPs — #71 of 99 Iowa counties.

Standout ZIPs in this County


Most Populous
Rockwell City · 3,034 people
29.2% of county total
Highest Income
Knierim · $89,000 median
1.3× county average
Largest Land Area
Rockwell City · 142.3 sq mi
Spans the most ground
Fastest Growth
Rockwell City · 10.9% (10-yr)
2,735 → 3,034 residents
Most Educated
Manson · 32.8% bachelor's+
566 of 1,727 adults 25+

Things worth knowing about Calhoun County


10,375 residents live across 10 ZIPs covering 614 sq mi, served by 10 distinct USPS-recognized cities.

Population moved from 10,798 to 10,299 from 2014 to 2024 — a -4.6% change. 3 ZIPs gained residents, 6 lost.

The county's wealthiest ZIP 50552 (Knierim, $89,000 median) and poorest ZIP 50575 (Pomeroy, $52,717) are 14.2 miles apart — a 1.7× income gap across local geography.

Median home values vary 3.2× across this county — from $51,100 in 50551 (Jolley) to $161,100 in 50563 (Manson).

Density varies 44× across the county — from 3 people/sq mi in 50551 (Jolley) to 152 in 50552 (Knierim).

Educational attainment ranges from 10.0% bachelor's+ in 50586 (Somers) to 32.8% in 50563 (Manson) — the breadth of educational profiles across the area.

Within Iowa, this is the #71 most populous of 99 counties and ranks #73 for median household income .

Weighted by population, the typical household earns about $67,404 across the county — reflecting what a typical resident sees, not a simple ZIP average.

21.9% of adults age 25+ hold a bachelor's degree or higher (1,615 of 7,391 reporting).

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

Stories about Calhoun County


Big & sparse

A frontier county — vast land area with only a few residents per square mile. Daily life looks very different here than in the country's denser counties.

Total area
614
square miles
Avg density
16.9
people per sq mi
Population
10,375
across 10 ZIPs
Rockwell City
142.3 sq mi
3,034 residents
Manson
101.5 sq mi
2,505 residents
Lake City
89.9 sq mi
1,950 residents

All ZIP Codes in Calhoun County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
50579Rockwell CityStandard3,034$61,108142.310.9%
50563MansonStandard2,505$71,094101.5-0.7%
51449Lake CityStandard1,950$75,32989.9-6.7%
50575PomeroyStandard696$52,71757.7-48.4%
50538FarnhamvilleStandard661$62,34432.634.9%
50561LyttonStandard585$67,44648.418.7%
51453LohrvilleStandard500$86,56379.6-27.8%
50586SomersStandard272$55,37533.2-14.7%
50551JolleyStandard9627.9-11.1%
50552KnierimPO Box76$89,0000.5

Adjacent & Nearby Counties