Franklin is a city in Warren County, Ohio, United States, along the Great Miami River. The population was 11,690 at the 2020 census. The city lies about 15 miles (24 km) southwest of Dayton and 33.5 miles (53.9 km) northeast of Cincinnati. Ohio State Routes 73, 123 and 741 pass through Franklin, while Interstate 75 is routed to the east side of the city.