ZIP Codes of Mercer County, OH

Population & People
Population & People
Total Population
42,549
Household Income
Household Income
Median Income
$84,006
Housing
Housing
Total Housing Units
18,066
Business & Economy
Business & Economy
Total Businesses
1,044
Employment
Employment
Employment Rate
65.85%
Education
Education
Bachelor's Degree+
22.01%
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 (7 Standard, 3 PO Box, 0 Unique) [See All]
Area Codes:419 / 567
Timezone:Eastern (GMT -05:00)
Local Time:2:13:21 PM
Population:42,549 [See All]
FIPS:39107
CBSA:Celina, OH
Land Area:478 sq mi
Water Area:11 sq mi
Coordinates:40.4868, -84.6103
Quick Link:
https://www.zip-codes.com/county/oh-mercer.asp
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Notable income spread
Median income ranges $45,556 to $113,967 across ZIPs — a 2.5× gap.

Standout ZIPs in this County


Most Populous
Celina · 19,957 people
46.9% of county total
Highest Income
Saint Henry · $113,967 median
1.4× county average
Largest Land Area
Celina · 175.1 sq mi
Spans the most ground
Fastest Growth
Fort Recovery · 10.3% (10-yr)
4,211 → 4,644 residents
Most Educated
Saint Henry · 30.9% bachelor's+
736 of 2,380 adults 25+

Things worth knowing about Mercer County


42,549 residents live across 10 ZIPs covering 478 sq mi, served by 10 distinct USPS-recognized cities.

Population moved from 40,826 to 42,549 from 2014 to 2024 — a +4.2% change. 9 ZIPs gained residents, 1 lost.

The county's wealthiest ZIP 45883 (Saint Henry, $113,967 median) and poorest ZIP 45862 (Mendon, $45,556) are 20.1 miles apart — a 2.5× income gap across local geography.

Median home values vary 2.7× across this county — from $108,200 in 45862 (Mendon) to $297,000 in 45883 (Saint Henry).

Density varies 48× across the county — from 34 people/sq mi in 45882 (Rockford) to 1,640 in 45826 (Chickasaw).

Educational attainment ranges from 9.9% bachelor's+ in 45862 (Mendon) to 30.9% in 45883 (Saint Henry) — the breadth of educational profiles across the area.

Within Ohio, this is the #58 most populous of 88 counties and ranks #14 for median household income .

Weighted by population, the typical household earns about $79,276 across the county — reflecting what a typical resident sees, not a simple ZIP average.

22.0% of adults age 25+ hold a bachelor's degree or higher (6,224 of 28,275 reporting).

7 Standard delivery, 3 PO Box only, 0 single-entity Unique ZIPs serve this county.

All ZIP Codes in Mercer County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
45822CelinaStandard19,957$70,200175.12.7%
45828ColdwaterStandard6,404$72,70334.15.4%
45846Fort RecoveryStandard4,644$91,73674.010.3%
45883Saint HenryStandard4,144$113,96738.72.7%
45882RockfordStandard2,919$74,62585.32.7%
45860Maria SteinStandard2,326$111,26933.68.9%
45862MendonStandard1,417$45,55636.66.8%
45826ChickasawPO Box394$101,2500.213.5%
45310BurkettsvillePO Box227$77,9170.25.1%
45866MontezumaPO Box117$80,8330.1-42.9%

Adjacent & Nearby Counties