Warren County, Ohio

Warren County is a county in Ohio, United States, about 22 miles northeast of Cincinnati between
Cincinnati and Dayton. It had a population of 242,337 at the 2020 census, an estimated 257,181 by
2025, and covers 407 square miles (1,050 km2) centred near 39°26′N 84°10′W.

Lebanon is the county seat; its postal code is 45036. Mason is the county’s largest city. The
county holds 9 cities, 8 incorporated villages and dozens of smaller communities across 11
townships, and it runs on Eastern Time.

Towns & Villages in Warren County

Warren County has 17 incorporated cities and villages, 6 census-designated places, and more than
30 smaller unincorporated communities. CDP stands for census designated place; Unincorp. covers
crossroads and rural communities with no formal boundary. Several cities extend into neighbouring
counties — the Type column notes where a place is only partly inside Warren County.

The old list on this page mixed genuine settlements with mobile-home parks and trailer courts
(Mason MH Park, Shawnee MH Court, Smittys Trailer Court) that are not places of record, and it
listed Roachester twice. Both errors are fixed above. Monroe, Springboro, Carlisle, Loveland,
Middletown and Blanchester each straddle Warren’s county line, so their population figures cover
their whole city or village, not just the Warren County share.

Townships

Warren County has 11 civil townships. Washington is the only one with no incorporated
municipality inside it.

ZIP Codes

• 45036 — Lebanon
• 45040 — Mason
• 45005 — Franklin (also serves Carlisle’s Warren County side)
• 45066 — Springboro (also 45342 for the Montgomery County side)
• 45065 — South Lebanon
• 45050 — Monroe (also 45044, 45073, 45099)
• 45068 — Waynesville (also serves Corwin)
• 45152 — Morrow
• 45039 — Maineville
• 45140 — Landen and Loveland Park (Loveland exchange)
• 45034 — Kings Mills (Mason exchange)
• 45032 — Harveysburg
• 45162 — Pleasant Plain (also serves Butlerville)
• 45054 — Oregonia
• 45107 — Blanchester (Clinton County post office, serves the Warren County edge)

Five Points, Hunter, Roachester and most other unincorporated communities have no ZIP of their
own; mail there is delivered under the nearest incorporated town’s code.

Geography

Warren County sits in southwestern Ohio, roughly square in shape, with sides about 20 miles (32
km) long. Of its 407 square miles, 401 are land and 6.0 are water, about 1.5 percent of the total.
The Little Miami River, a National Scenic River, crosses the county from northeast to southwest
and forms much of the Little Miami Scenic Trail corridor. Caesar Creek, dammed in the 1970s to
form Caesar Creek Lake, drains the county’s eastern townships. The county’s highest point is in
Clearcreek Township near Five Points.

Montgomery and Greene counties border Warren to the north, Clinton County to the east, Clermont
County to the southeast, Hamilton County to the southwest, and Butler County to the west. Montgomery County, Greene County, Clinton County, Clermont County, Hamilton County and Butler County all border Warren
directly.

Demographics

Warren County had a population of 242,337 at the 2020 census, and the latest estimate puts it
near 257,181 residents by 2025. Mason and Lebanon are the two largest communities, though Deerfield
Township — which contains Mason, Kings Mills and Landen — is the most populous of the
11 townships at 40,525. Median household income runs $110,132 (2024 ACS), well above Ohio’s 2023
ACS statewide figure of $67,769; the county consistently ranks among the two highest-income
counties of Ohio’s 88. Population density works out to roughly 604 people per square mile of
land, dense for a county without a single dominant urban core, reflecting its position between the
Cincinnati and Dayton metropolitan areas.

Economy & Local Life

Manufacturing employs the most workers in the county, about 21,122 people, followed by health
care and social assistance at 17,495 and professional, scientific and technical services at
14,104. Procter & Gamble’s Mason Business Center, a global research and innovation facility,
is the county’s single largest employer at roughly 3,036 workers. Macy’s, LensCrafters parent
Luxottica, Cintas and Anthem also run major operations in Mason and Lebanon. Kings Island amusement
park and the adjoining Great Wolf Lodge water park, both in Deerfield Township near Kings Mills,
draw millions of visitors a year and are among the county’s largest seasonal employers. The
county’s biggest annual event is the Ohio Renaissance Festival in Harveysburg, running weekends
from late August through late October.

History

The Northwest Territory legislature created Warren County on 1 May 1803, carving it from
Hamilton County. It was named for Dr. Joseph Warren, a physician and general killed at the Battle
of Bunker Hill in 1775. Lebanon, platted in September 1802, became the county seat and took its
name from the biblical cedars of Lebanon, a reference to the juniper and red cedar trees native to
the area.

Fort Ancient, in Washington Township along the Little Miami River, is a 2,000-year-old
hilltop enclosure built by the Hopewell culture and is a National Historic Landmark. Union Village,
in Turtlecreek Township near Lebanon, was a Shaker religious community founded in 1805 that
operated until 1912, one of the longest-lived Shaker settlements west of the Appalachians. Harvey
family abolitionists in Harveysburg opened the Harvey Free Negro School in 1831, one of Ohio’s
first schools for Black children.

Getting There

Interstate 71 and Interstate 75 both cross the county, along with US 22, US 42 and several state
routes. No interstate directly serves Waynesville or Harveysburg in the county’s southeast
corner, which relies on US 42 and state routes instead.

• Cincinnati — about 22 miles southwest
• Dayton — about 20 miles north
• Xenia — about 15 miles northeast
• Batavia — about 20 miles southeast

Cincinnati/Northern Kentucky International Airport, roughly 40 miles southwest of Lebanon, is
the nearest major commercial airport; Dayton International Airport is a comparable distance to the
north. Amtrak does not serve Warren County directly — the nearest station is Cincinnati Union
Terminal, served by the Cardinal line.

Frequently Asked Questions

Where is Warren County located?
It sits in southwestern Ohio between Cincinnati and Dayton, bordered by Montgomery, Greene,
Clinton, Clermont, Hamilton and Butler counties.

What is the population of Warren County?
242,337 at the 2020 census, with a 2025 estimate near 257,181.

How big is Warren County?
407 square miles (1,050 km2), of which 401 square miles are land.

What is the county seat of Warren County?
Lebanon is the county seat; Mason, with 34,792 residents at the 2020 census, is the largest city.

How many towns and cities are in Warren County?
Seventeen incorporated cities and villages, six census-designated places, and more than 30
unincorporated communities, spread across 11 townships.

What ZIP codes does Warren County use?
45036 for Lebanon, 45040 for Mason, 45005 for Franklin and Carlisle, 45066 for Springboro, and
smaller codes such as 45068 (Waynesville), 45152 (Morrow) and 45162 (Pleasant Plain and
Butlerville).

What is Warren County known for?
Kings Island amusement park, the Ohio Renaissance Festival in Harveysburg, and Fort Ancient, a
2,000-year-old Hopewell earthwork on the Little Miami River.

Is Warren County a wealthy county?
Yes. Its 2024 median household income of $110,132 ranks among the two highest of Ohio’s 88
counties, well above the state figure of $67,769 (2023 ACS).

More counties in this state: Towns and villages in Ohio.