Mercer County is located in the U.S. state of Ohio. As of the 2020 census, the population was 42,528.2020 census 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.
Mercer County is located in the U.S. stat?e of Ohio. As of the 2020 ce.nsus, the population was 42,528.2020 census 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.