Union County is a county in Ohio, United States, part of the Columbus metropolitan area on the region’s north-west edge. It had a population of 62,784 at the 2020 census and covers 432 square miles (1,120 km2) of land plus 5.1 square miles (13 km2) of water, centred near 40°19′N 83°22′W.
Marysville is the county seat, and its postal code is 43040. The county has one city (Marysville), several villages, and 14 civil townships. It sits in the Eastern time zone.
Towns & Villages in Union County
Union County’s largest incorporated places are Marysville and the villages of Richwood, Milford Center, Magnetic Springs, and Unionville Center; two of Ohio’s fast-growing Columbus-suburb communities, Dublin and Plain City, extend into the county’s eastern townships but are seated primarily in neighboring counties. The rest of the list below is unincorporated communities, subdivisions, and manufactured-home parks (marked Unincorp.).
| Place | Type | Township | Pop. | ZIP |
|---|---|---|---|---|
| Marysville | City · seat | Paris | — | 43040 |
| Richwood | Village | Claibourne | — | 43344 |
| Milford Center | Village | Allen | — | 43045 |
| Magnetic Springs | Village | Taylor | — | 43036 |
| Unionville Center | Village | Liberty | — | 43077 |
| Plain City | Village (partial) | Jerome | — | — |
| Dublin | City (partial) | Jerome | — | — |
| Irwin | Unincorp. | Jackson | — | 43029 |
| Raymond | Unincorp. | Union | — | 43067 |
| Broadway | Unincorp. | Leesburg | — | 43007 |
| New California | Unincorp. | Darby | — | — |
| New Dover | Unincorp. | Dover | — | — |
| Pottersburg | Unincorp. | Dover | — | — |
| Pharisburg | Unincorp. | Washington | — | — |
| Peoria | Unincorp. | Washington | — | — |
| West Jackson | Unincorp. | Jackson | — | — |
| Watkins | Unincorp. | Jackson | — | — |
| Byhalia | Unincorp. | York | — | — |
| York Center | Unincorp. | York | — | — |
| Jerome | Unincorp. | Jerome | — | — |
| Claiborne | Unincorp. | Claibourne | — | — |
| Chuckery | Unincorp. | Union | — | — |
| Arbela | Unincorp. | Millcreek | — | — |
| Otter | Unincorp. | Millcreek | — | — |
| Essex | Unincorp. | Liberty | — | — |
| Dipple | Unincorp. | — | — | — |
| Lunda | Unincorp. | — | — | — |
| Summersville | Unincorp. | — | — | — |
| Woodland | Unincorp. | — | — | — |
| Pleasant Ridge | Unincorp. | — | — | — |
| Adena Pointe | Unincorp. | Paris | — | — |
| Allen Center | Unincorp. | Allen | — | — |
| Ashton Meadows | Unincorp. | — | — | — |
| Bridgeport | Unincorp. | — | — | — |
| Buxton Meadows | Unincorp. | — | — | — |
| Carriage Acres | Unincorp. | — | — | — |
| Countryside MH Park | Unincorp. | — | — | — |
| Darby Meadows | Unincorp. | Darby | — | — |
| Fleetwood Park | Unincorp. | — | — | — |
| Green Pastures | Unincorp. | — | — | — |
| Greenwood Colony | Unincorp. | — | — | — |
| Hickory Run | Unincorp. | — | — | — |
| Hillcrest MH Park | Unincorp. | — | — | — |
| Hunters Run | Unincorp. | — | — | — |
| Marysville Estates | Unincorp. | Paris | — | — |
| Milford Estates | Unincorp. | Allen | — | — |
| Mill Creek Estates | Unincorp. | Millcreek | — | — |
| Millcreek Meadows | Unincorp. | Millcreek | — | — |
| Parrott Village | Unincorp. | — | — | — |
| Tawa Estates | Unincorp. | — | — | — |
| Troyer MH Park | Unincorp. | — | — | — |
| Woodview Park | Unincorp. | — | — | — |
Dublin and Plain City both straddle the Union/Franklin and Union/Madison county lines; only their Union County wards are addressed here, and their main civic centers sit in the neighboring county.
Townships
| Township | Pop. (2020) | Main settlements |
|---|---|---|
| Paris | — | Marysville (seat) |
| Jerome | — | Plain City (partial), Dublin (partial) |
| Claibourne | — | Richwood |
| Allen | — | Milford Center |
| Liberty | — | Unionville Center |
| Taylor | — | Magnetic Springs |
| Jackson | — | Irwin, West Jackson, Watkins |
| Union | — | Raymond, Chuckery |
| Leesburg | — | Broadway |
| Darby | — | New California |
| Dover | — | New Dover, Pottersburg |
| Washington | — | Pharisburg, Peoria |
| York | — | Byhalia, York Center |
| Millcreek | — | Arbela, Otter |
ZIP Codes
- 43040 — Marysville (also serves Adena Pointe, Marysville Estates)
- 43041 — Marysville (unique ZIP)
- 43344 — Richwood
- 43067 — Raymond
- 43045 — Milford Center
- 43029 — Irwin
- 43036 — Magnetic Springs
- 43077 — Unionville Center
- 43007 — Broadway
Most of the county’s population sits in the 43040 ZIP: 77.9% of residents (38,990 of 50,021 counted in that code). Small unincorporated crossroads not listed above share a ZIP with their nearest post-office town.
Geography
Union County lies on the till plains of west-central Ohio, drained by the Big Darby Creek and Mill Creek watersheds in a landscape of flat-to-gently-rolling farmland. The county borders Marion County to the north-east, Delaware County to the east, Franklin County to the south-east, Madison County to the south, Champaign County to the south-west, Logan County to the west, and Hardin County to the north-west. Marion County, Delaware County, and Franklin County complete the ring around it.
Demographics
Union County counted 62,784 residents at the 2020 census, up sharply from prior counts as Columbus-area growth pushed north-west along the US 33 corridor. Marysville, the county seat, is by far the largest community; Richwood is the county’s second-largest incorporated place. Median household income runs above the Ohio median of $67,769, reflecting the county’s mix of manufacturing wages and Columbus-commuter households. Overall density is roughly 145 people per square mile, though most of that population concentrates in and around Marysville.
Economy & Local Life
Manufacturing anchors the local economy. Honda of America Mfg. operates its original U.S. auto assembly and engine plants in Marysville, and Scotts Miracle-Gro is headquartered in the city as well, both major employers for the county. Farming remains significant across the townships, with corn and soybeans the dominant crops. The Union County Fair, held each July at the fairgrounds in Marysville, is the county’s largest annual community event.
History
Union County organized on April 1, 1820, assembled from parts of Franklin, Delaware, Madison, and Logan counties — the merger that gives the county its name. Marysville was platted as the seat soon after organization. The county grew as an agricultural trade center through the 19th and early 20th centuries before Honda’s arrival in 1979 turned Marysville into a major manufacturing hub and accelerated the county’s growth as Columbus expanded outward.
Getting There
US 33 runs diagonally through the county connecting Marysville to Columbus, and US 36 and US 42 cross the county east-west and north-south respectively. State Routes 4, 31, 37, 38, 47, 161, 245, 347, and 736 fill out the local network.
- Columbus — 25 miles south-east
- Bellefontaine — 20 miles west
- Delaware — 20 miles east
- Kenton — 25 miles north-west
The nearest commercial airport is John Glenn Columbus International Airport, about 30 miles south-east of Marysville.
Frequently Asked Questions
Where is Union County, Ohio?
It sits in west-central Ohio, on the north-west edge of the Columbus metropolitan area, centred near 40°19′N 83°22′W.
What is the population of Union County?
62,784 people, per the 2020 census.
How big is Union County?
432 square miles (1,120 km2) of land plus 5.1 square miles (13 km2) of water.
What is the county seat of Union County?
Marysville is the county seat.
How many towns are in Union County?
One city (Marysville) and four villages (Richwood, Milford Center, Magnetic Springs, Unionville Center), plus 14 townships and numerous unincorporated communities.
What ZIP codes are in Union County?
43040 and 43041 (Marysville), 43344 (Richwood), 43067 (Raymond), 43045 (Milford Center), 43029 (Irwin), 43036 (Magnetic Springs), 43077 (Unionville Center), and 43007 (Broadway).
Where is Honda’s Marysville plant?
Honda of America Mfg. operates its original U.S. auto assembly and engine plants in Marysville, Union County’s largest city.
More counties in this state: Towns and villages in Ohio.