ZIP Codes of Allen County, KS

Population & People
Population & People
Total Population
12,370
Household Income
Household Income
Median Income
$65,188
Housing
Housing
Total Housing Units
6,071
Business & Economy
Business & Economy
Total Businesses
348
Employment
Employment
Employment Rate
57.40%
Education
Education
Bachelor's Degree+
22.72%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 7 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:7 ZIP Codes (6 Standard, 1 PO Box, 0 Unique) [See All]
Area Code:620
Timezone:Central (GMT -06:00)
Local Time:2:12:10 PM
Population:12,370 [See All]
FIPS:20001
Land Area:494 sq mi
Water Area:5 sq mi
Coordinates:37.8611, -95.2993
Quick Link:
https://www.zip-codes.com/county/ks-allen.asp
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Kansas's #36 most populous county
12,370 residents across 7 ZIPs — #36 of 106 Kansas counties.

Standout ZIPs in this County


Most Populous
Iola · 7,448 people
60.2% of county total
Highest Income
Elsmore · $87,625 median
1.3× county average
Largest Land Area
Moran · 122.8 sq mi
Spans the most ground
Fastest Growth
Humboldt · 18.5% (10-yr)
2,389 → 2,830 residents
Most Educated
Iola · 25.2% bachelor's+
1,214 of 4,812 adults 25+

Things worth knowing about Allen County


12,370 residents live across 7 ZIPs covering 494 sq mi, served by 7 distinct USPS-recognized cities.

Population moved from 13,049 to 12,340 from 2014 to 2024 — a -5.4% change. 2 ZIPs gained residents, 4 lost.

The county's wealthiest ZIP 66732 (Elsmore, $87,625 median) and poorest ZIP 66751 (La Harpe, $48,417) are 9.5 miles apart — a 1.8× income gap across local geography.

Median home values vary 3.6× across this county — from $57,700 in 66751 (La Harpe) to $206,600 in 66772 (Savonburg).

Density varies 11× across the county — from 6 people/sq mi in 66732 (Elsmore) to 65 in 66749 (Iola).

Educational attainment ranges from 7.0% bachelor's+ in 66732 (Elsmore) to 25.3% in 66755 (Moran) — the breadth of educational profiles across the area.

Within Kansas, this is the #36 most populous of 106 counties and ranks #59 for median household income .

Weighted by population, the typical household earns about $61,187 across the county — reflecting what a typical resident sees, not a simple ZIP average.

22.7% of adults age 25+ hold a bachelor's degree or higher (1,907 of 8,392 reporting).

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

Stories about Allen 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.

Iola

Population decline

Allen County lost 5.2% of residents between 2014 and 2024. ZIPs that shed the largest share:

La Harpe
-46.8%
1,110 → 590 residents
Moran
-24.6%
1,180 → 890 residents

All ZIP Codes in Allen County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
66749IolaStandard7,448$60,093115.3-4.1%
66748HumboldtStandard2,830$59,871111.118.5%
66755MoranStandard890$74,417122.8-24.6%
66751La HarpeStandard590$48,41746.1-46.8%
66732ElsmoreStandard294$87,62550.012.6%
66772SavonburgStandard288$60,70348.2-15.5%
66742GasPO Box300.0

Adjacent & Nearby Counties