Your Guide to Hamilton County, Ohio
Looking for trusted businesses, services and local resources in Hamilton County, Ohio? FindItOhio.com helps residents and visitors discover local companies, professionals and community information across Hamilton County, including Cincinnati, the county seat.
Quick answer: Hamilton County is one of Ohio’s 88 counties. Its county seat is Cincinnati, it was established in 1790, and it has an estimated 838,418 residents as of 2025.
At a Glance
- County seat: Cincinnati
- Established: Jan 2, 1790
- Formed from: One of the original counties
- Named for: Alexander Hamilton (1755/7 to 1804), Secretary of the Treasury when the county was organized
- Estimated population (2025): 838,418
- Total area: 407.36 sq mi
- FIPS code: 39061
About Hamilton County
Hamilton County is located in the southwestern corner of the U.S. state of Ohio. As of the 2020 census, the population was 830,639, making it the third most populous county in Ohio. The county seat and most populous city is Cincinnati. The county is named for the first Secretary of the Treasury, Alexander Hamilton. Hamilton County is part of the Cincinnati, Middletown, OH, KY, IN Metropolitan Statistical Area.
History of Hamilton County
The southern portion of Hamilton County was originally owned and surveyed by John Cleves Symmes, and the region was a part of the Symmes Purchase. The first settlers rafted down the Ohio River in 1788 following the American Revolutionary War. They established the towns of Losantiville (later Cincinnati), North Bend, and Columbia.
Hamilton County was organized in 1790 by order of Arthur St. Clair, governor of the Northwest Territory, as the second county in the Northwest Territory. Cincinnati was named as the seat. Residents named the county in honor of Alexander Hamilton, who was the first Secretary of the Treasury of the United States and a founder of the Federalist Party. Its original boundaries were those defined for the Symmes purchase contract in 1788: the Ohio River in the South, Great Miami River to the west, the Lesser Miami River to the east, and the Cuyahoga River to the North. Its area then included about one eighth of Ohio and had about 2,000 inhabitants (not including the remaining Native Americans).
Cities and Villages in Hamilton County
Cities
Blue Ash, Cheviot, Cincinnati †, Deer Park, Fairfield, Forest Park, Harrison, Loveland, Madeira, Milford, Montgomery, Mount Healthy, North College Hill, Norwood, Reading, Sharonville, Springdale, The Village of Indian Hill, Wyoming
Villages
Addyston, Amberley, Arlington Heights, Cleves, Elmwood Place, Evendale, Fairfax, Glendale, Golf Manor, Greenhills, Lincoln Heights, Lockland, Mariemont, Newtown, North Bend, Silverton, St. Bernard, Terrace Park, Woodlawn
Find Local Businesses in Hamilton County
Browse the FindItOhio.com business directory to find restaurants, contractors, professional services, shops and more serving Hamilton County. Own a business here? Add your free business listing so local customers can find you.
Background Checks, Process Serving and Private Investigations
Residents and employers in Hamilton County can get BCI and FBI LiveScan fingerprinting, FD-258 fingerprint cards, process serving and licensed private investigations from these Ohio providers:
- Ohio Security & Investigations, Youngstown: licensed private investigations and fingerprinting. Call (888) 341-6960 or visit ohioinvestigators.com.
- 10-8 Protective Services, Columbus: investigations, fingerprinting and process serving. Call (800) 949-8521 or visit 10-8protectiveservices.com.
Frequently Asked Questions
What is the county seat of Hamilton County, Ohio?
Cincinnati is the county seat of Hamilton County, Ohio.
When was Hamilton County established?
Hamilton County was established on Jan 2, 1790. It was formed from One of the original counties.
Who or what is Hamilton County named for?
Hamilton County is named for Alexander Hamilton (1755/7 to 1804), Secretary of the Treasury when the county was organized.
How many people live in Hamilton County, Ohio?
Hamilton County has an estimated population of 838,418 as of 2025.
What cities are in Hamilton County, Ohio?
Cities in Hamilton County include Blue Ash, Cheviot, Cincinnati †, Deer Park, Fairfield, Forest Park, Harrison, Loveland and others.
Where can I find local businesses in Hamilton County?
Search the FindItOhio.com business directory to find local businesses and services in Hamilton County, Ohio.
How do I list my Hamilton County business on FindItOhio.com?
Visit the free business listing page on FindItOhio.com and submit your business name, address, phone number and website.
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County background adapted from the Wikipedia article Hamilton County, Ohio, available under the Creative Commons Attribution ShareAlike 4.0 license.