Your Guide to Mercer County, Ohio
Looking for trusted businesses, services and local resources in Mercer County, Ohio? FindItOhio.com helps residents and visitors discover local companies, professionals and community information across Mercer County, including Celina, the county seat.
Quick answer: Mercer County is one of Ohio’s 88 counties. Its county seat is Celina, it was established in 1820, and it has an estimated 42,737 residents as of 2025.
At a Glance
- County seat: Celina
- Established: Apr 1, 1820
- Formed from: Darke County
- Named for: General Hugh Mercer (1726 to 1777), a Revolutionary War officer
- Estimated population (2025): 42,737
- Total area: 463.27 sq mi
- FIPS code: 39107
About Mercer County
Mercer County is located in the U.S. state of Ohio. As of the 2020 census, the population was 42,528. Its county seat is Celina. The county was created in 1820 and later organized in 1824. It is named for Hugh Mercer, an officer in the American Revolutionary War.
History of Mercer County
Mercer County was created in 1820 from land that had been attached to Darke and Shelby counties. Land south of the Greenville Treaty Line was still part of Darke County. An act establishing and fully organizing Mercer County took place on January 2, 1824. In 1837 Van Wert County was detached and the county line established is the current northern border of Mercer County. In 1839 Celina was established as the seat of Mercer County; St. Marys was the previous seat. In 1848 the area south of the Greenville Treaty Line to the current southern county line, was attached. When Auglaize County was formed, Mercer County’s eastern border was moved 6 miles (9.7 km) west with the exception of the area south of the Greenville Treaty Line. This created the sharp point at Mercer County’s southeast corner and was the last county line modification.
In the mid to late 1800s, Mercer County became home to many German immigrant farming families. Many of these German Americans had immigrated from northwestern Germany.
Cities and Villages in Mercer County
Cities
Celina â€
Villages
Burkettsville, Chickasaw, Coldwater, Fort Recovery, Mendon, Montezuma, Rockford, St. Henry
Find Local Businesses in Mercer County
Browse the FindItOhio.com business directory to find restaurants, contractors, professional services, shops and more serving Mercer 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 Mercer 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 Mercer County, Ohio?
Celina is the county seat of Mercer County, Ohio.
When was Mercer County established?
Mercer County was established on Apr 1, 1820. It was formed from Darke County.
Who or what is Mercer County named for?
Mercer County is named for General Hugh Mercer (1726 to 1777), a Revolutionary War officer.
How many people live in Mercer County, Ohio?
Mercer County has an estimated population of 42,737 as of 2025.
What cities are in Mercer County, Ohio?
Cities in Mercer County include Celina †.
Where can I find local businesses in Mercer County?
Search the FindItOhio.com business directory to find local businesses and services in Mercer County, Ohio.
How do I list my Mercer County business on FindItOhio.com?
Visit the free business listing page on FindItOhio.com and submit your business name, address, phone number and website.
Looking for another county? Explore all 88 Ohio counties on FindItOhio.com.
County background adapted from the Wikipedia article Mercer County, Ohio, available under the Creative Commons Attribution ShareAlike 4.0 license.