ZIP Codes of Union County, OH

Population & People
Population & People
Total Population
50,021
Household Income
Household Income
Median Income
$95,059
Housing
Housing
Total Housing Units
19,338
Business & Economy
Business & Economy
Total Businesses
775
Employment
Employment
Employment Rate
64.74%
Education
Education
Bachelor's Degree+
30.31%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 9 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:9 ZIP Codes (5 Standard, 3 PO Box, 1 Unique) [See All]
Area Codes:220 / 326 / 740 / 937
Timezone:Eastern (GMT -05:00)
Local Time:2:13:22 PM
Population:50,021 [See All]
FIPS:39159
CBSA:Columbus, OH
Land Area:362 sq mi
Water Area:4 sq mi
Coordinates:40.2640, -83.3926
Quick Link:
https://www.zip-codes.com/county/oh-union.asp
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Among Ohio's 5 fastest-growing counties
#2 statewide, up 19.1% from 2014 to 2024.

Standout ZIPs in this County


Most Populous
Marysville · 38,990 people
77.9% of county total
Highest Income
Irwin · $107,744 median
1.1× county average
Largest Land Area
Marysville · 169.6 sq mi
Spans the most ground
Fastest Growth
Raymond · 71.1% (10-yr)
1,101 → 1,884 residents
Most Educated
Marysville · 33.5% bachelor's+
9,253 of 27,594 adults 25+

Things worth knowing about Union County


50,021 residents live across 9 ZIPs covering 362 sq mi, served by 8 distinct USPS-recognized cities.

Population moved from 41,993 to 49,958 from 2014 to 2024 — a +19.0% change. 5 ZIPs gained residents, 2 lost.

The county's wealthiest ZIP 43029 (Irwin, $107,744 median) and poorest ZIP 43036 (Magnetic Springs, $77,813) are 19.7 miles apart — a 1.4× income gap across local geography.

Median home values vary 2.3× across this county — from $137,500 in 43036 (Magnetic Springs) to $311,100 in 43040 (Marysville).

Density varies 129× across the county — from 24 people/sq mi in 43029 (Irwin) to 3,116 in 43036 (Magnetic Springs).

Educational attainment ranges from 14.7% bachelor's+ in 43344 (Richwood) to 33.5% in 43040 (Marysville) — the breadth of educational profiles across the area.

Within Ohio, this is the #49 most populous of 88 counties and ranks #6 for median household income with the #2 fastest decade growth .

Hosts 1 single-entity Unique ZIP: 43041O M Scott Co .

Weighted by population, the typical household earns about $96,877 across the county — reflecting what a typical resident sees, not a simple ZIP average.

30.3% of adults age 25+ hold a bachelor's degree or higher (10,625 of 35,060 reporting).

5 Standard delivery, 3 PO Box only, 1 single-entity Unique ZIPs serve this county.

Stories about Union 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.

Marysville

All ZIP Codes in Union County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
43040MarysvilleStandard38,990$99,321169.619.9%
43344RichwoodStandard6,173$80,90999.213.9%
43067RaymondStandard1,884$95,90332.871.1%
43045Milford CenterStandard1,739$99,18138.10.8%
43029IrwinStandard544$107,74422.5-13.8%
43036Magnetic SpringsPO Box359$77,8130.134.0%
43077Unionville CenterPO Box269$104,5450.1-21.1%
43007BroadwayPO Box630.0
43041MarysvilleUnique0.0

Adjacent & Nearby Counties