ZIP Codes of Obrien County, IA

Population & People
Population & People
Total Population
14,685
Household Income
Household Income
Median Income
$73,638
Housing
Housing
Total Housing Units
6,710
Business & Economy
Business & Economy
Total Businesses
508
Employment
Employment
Employment Rate
65.48%
Education
Education
Bachelor's Degree+
21.86%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 8 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:8 ZIP Codes (7 Standard, 1 PO Box, 0 Unique) [See All]
Area Code:712
Timezone:Central (GMT -06:00)
Local Time:2:11:54 PM
Population:14,685 [See All]
FIPS:19141
Land Area:627 sq mi
Water Area:0 sq mi
Coordinates:43.0823, -95.6282
Quick Link:
https://www.zip-codes.com/county/ia-obrien.asp
Need Obrien data in your app? Look up ZIP, county, and city data with a single API call.
Try Free
Iowa's #52 most populous county
14,685 residents across 8 ZIPs — #52 of 99 Iowa counties.

Standout ZIPs in this County


Most Populous
Sheldon · 6,430 people
43.8% of county total
Highest Income
Archer · $108,058 median
1.5× county average
Largest Land Area
Hartley · 150.6 sq mi
Spans the most ground
Fastest Growth
Hartley · 4.6% (10-yr)
2,148 → 2,247 residents
Most Educated
Hartley · 21.9% bachelor's+
358 of 1,637 adults 25+

Things worth knowing about Obrien County


14,685 residents live across 8 ZIPs covering 627 sq mi, served by 8 distinct USPS-recognized cities.

Population moved from 14,670 to 14,685 from 2014 to 2024 — a +0.1% change. 4 ZIPs gained residents, 4 lost.

The county's wealthiest ZIP 51231 (Archer, $108,058 median) and poorest ZIP 51009 (Calumet, $58,750) are 14.9 miles apart — a 1.8× income gap across local geography.

Median home values vary 2.4× across this county — from $83,300 in 51009 (Calumet) to $197,800 in 51201 (Sheldon).

Density varies 31× across the county — from 13 people/sq mi in 51058 (Sutherland) to 405 in 51009 (Calumet).

Educational attainment ranges from 19.7% bachelor's+ in 51046 (Paullina) to 33.5% in 51231 (Archer) — the breadth of educational profiles across the area.

Within Iowa, this is the #52 most populous of 99 counties and ranks #50 for median household income .

Weighted by population, the typical household earns about $71,339 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 (2,182 of 9,983 reporting).

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

Stories about Obrien 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
627
square miles
Avg density
23.4
people per sq mi
Population
14,685
across 8 ZIPs
Hartley
150.6 sq mi
2,247 residents
Sheldon
112.5 sq mi
6,430 residents
Paullina
93.8 sq mi
1,326 residents

All ZIP Codes in Obrien County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
51201SheldonStandard6,430$68,799112.54.5%
51346HartleyStandard2,247$72,426150.64.6%
51248SanbornStandard1,534$64,37580.2-2.7%
51245PrimgharStandard1,377$69,53178.0-0.9%
51046PaullinaStandard1,326$84,12593.8-19.3%
51058SutherlandStandard1,096$63,03683.30.5%
51231ArcherStandard562$108,05827.755.2%
51009CalumetPO Box113$58,7500.3-62.8%

Adjacent & Nearby Counties