ZIP Codes of Hardin County, OH

Population & People
Population & People
Total Population
31,646
Household Income
Household Income
Median Income
$64,676
Housing
Housing
Total Housing Units
13,250
Business & Economy
Business & Economy
Total Businesses
427
Employment
Employment
Employment Rate
58.14%
Education
Education
Bachelor's Degree+
19.09%
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 (8 Standard, 2 PO Box, 0 Unique) [See All]
Area Codes:326 / 419 / 567 / 937
Timezone:Eastern (GMT -05:00)
Local Time:2:13:20 PM
Population:31,646 [See All]
FIPS:39065
Land Area:502 sq mi
Water Area:0 sq mi
Coordinates:40.6712, -83.6776
Quick Link:
https://www.zip-codes.com/county/oh-hardin.asp
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Ohio's #71 most populous county
31,646 residents across 10 ZIPs — #71 of 88 Ohio counties.

Standout ZIPs in this County


Most Populous
Kenton · 12,573 people
39.7% of county total
Highest Income
Ridgeway · $90,821 median
1.4× county average
Largest Land Area
Kenton · 189.4 sq mi
Spans the most ground
Fastest Growth
Alger · 12.1% (10-yr)
1,808 → 2,027 residents
Most Educated
Ada · 31.8% bachelor's+
1,110 of 3,491 adults 25+

Things worth knowing about Hardin County


31,646 residents live across 10 ZIPs covering 502 sq mi, served by 10 distinct USPS-recognized cities.

Population moved from 32,792 to 31,408 from 2014 to 2024 — a -4.2% change. 4 ZIPs gained residents, 4 lost (and 1 held flat).

The county's wealthiest ZIP 43345 (Ridgeway, $90,821 median) and poorest ZIP 45812 (Alger, $44,045) are 17.2 miles apart — a 2.1× income gap across local geography.

Median home values vary 2.6× across this county — from $77,900 in 45859 (Mc Guffey) to $201,600 in 43345 (Ridgeway).

Density varies 45× across the county — from 23 people/sq mi in 43345 (Ridgeway) to 1,030 in 45859 (Mc Guffey).

Educational attainment ranges from 4.8% bachelor's+ in 45859 (Mc Guffey) to 31.8% in 45810 (Ada) — the breadth of educational profiles across the area.

Within Ohio, this is the #71 most populous of 88 counties and ranks #64 for median household income .

Weighted by population, the typical household earns about $64,209 across the county — reflecting what a typical resident sees, not a simple ZIP average.

19.1% of adults age 25+ hold a bachelor's degree or higher (3,682 of 19,291 reporting).

8 Standard delivery, 2 PO Box only, 0 single-entity Unique ZIPs serve this county.

Stories about Hardin 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
502
square miles
Avg density
63.0
people per sq mi
Population
31,646
across 10 ZIPs
Kenton
189.4 sq mi
12,573 residents
Forest
88.3 sq mi
4,184 residents
Ada
65.1 sq mi
7,449 residents

All ZIP Codes in Hardin County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
43326KentonStandard12,573$63,785189.4-5.0%
45810AdaStandard7,449$63,45165.1-11.6%
45843ForestStandard4,184$71,54188.31.0%
43340Mount VictoryStandard2,103$72,44648.05.5%
45812AlgerStandard2,027$44,04538.312.1%
45836DunkirkStandard1,573$56,25024.30.0%
43345RidgewayStandard666$90,82129.1-8.3%
45835DolaStandard449$76,04219.316.9%
45859Mc GuffeyPO Box384$51,2500.4-24.6%
43346RoundheadPO Box238$57,1300.0

Adjacent & Nearby Counties