Franklin County is a
county in the
U.S. state of
Ohio. As of the
2010 census, the population was 1,163,414, making it the second-most populous county in Ohio. Its
county seat is
Columbus, the state capital and most populous city in Ohio. The county was established on April 30, 1803, less than two months after Ohio became a state, and was
named after
Benjamin Franklin. Franklin County originally extended all the way north to
Lake Erie before Ohio subdivided further into more counties.