ZIP Codes of Osceola County, IA

Population & People
Population & People
Total Population
5,917
Household Income
Household Income
Median Income
$69,721
Housing
Housing
Total Housing Units
2,823
Business & Economy
Business & Economy
Total Businesses
185
Employment
Employment
Employment Rate
63.07%
Education
Education
Bachelor's Degree+
16.79%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 5 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:5 ZIP Codes (5 Standard, 0 PO Box, 0 Unique) [See All]
Area Code:712
Timezone:Central (GMT -06:00)
Local Time:2:11:54 PM
Population:5,917 [See All]
FIPS:19143
Land Area:376 sq mi
Water Area:1 sq mi
Coordinates:43.3638, -95.6204
Quick Link:
https://www.zip-codes.com/county/ia-osceola.asp
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Iowa's #96 most populous county
5,917 residents across 5 ZIPs — #96 of 99 Iowa counties.

Standout ZIPs in this County


Most Populous
Sibley · 3,564 people
60.2% of county total
Highest Income
Ashton · $82,917 median
1.2× county average
Largest Land Area
Sibley · 130.2 sq mi
Spans the most ground
Fastest Growth
Sibley · 5.7% (10-yr)
3,371 → 3,564 residents
Most Educated
Sibley · 21.2% bachelor's+
522 of 2,468 adults 25+

Things worth knowing about Osceola County


5,917 residents live across 5 ZIPs covering 376 sq mi, served by 5 distinct USPS-recognized cities.

Population moved from 6,279 to 5,917 from 2014 to 2024 — a -5.8% change. 1 ZIPs gained residents, 4 lost.

The county's wealthiest ZIP 51232 (Ashton, $82,917 median) and poorest ZIP 51345 (Harris, $54,301) are 20.4 miles apart — a 1.5× income gap across local geography.

Median home values vary 2.0× across this county — from $79,300 in 51350 (Melvin) to $160,700 in 51249 (Sibley).

Density varies across the county — from 6 people/sq mi in 51345 (Harris) to 27 in 51249 (Sibley).

Educational attainment ranges from 5.6% bachelor's+ in 51354 (Ocheyedan) to 21.2% in 51249 (Sibley) — the breadth of educational profiles across the area.

Within Iowa, this is the #96 most populous of 99 counties and ranks #71 for median household income .

Weighted by population, the typical household earns about $66,296 across the county — reflecting what a typical resident sees, not a simple ZIP average.

16.8% of adults age 25+ hold a bachelor's degree or higher (704 of 4,192 reporting).

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

Stories about Osceola 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.

Sibley

Population decline

Osceola County lost 5.8% of residents between 2014 and 2024. ZIPs that shed the largest share:

Melvin
-39.9%
637 → 383 residents
Ashton
-13.5%
761 → 658 residents
Ocheyedan
-13.0%
1,109 → 965 residents

All ZIP Codes in Osceola County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
51249SibleyStandard3,564$61,500130.25.7%
51354OcheyedanStandard965$72,63985.0-13.0%
51232AshtonStandard658$82,91764.3-13.5%
51350MelvinStandard383$77,25040.2-39.9%
51345HarrisStandard347$54,30155.9-13.5%

Adjacent & Nearby Counties