Lima is a city in and the county seat of Allen County, Ohio, United States. The municipality is located in northwestern Ohio along Interstate 75 approximately 72 miles north of Dayton and 78 miles south-southwest of Toledo.As of the 2010 census, the city had a population of 38,771. It is the principal city of and is included in the Lima, Ohio metropolitan statistical area, which is included in the Lima?Van Wert?Wapakoneta, OH, combined statistical area. Lima was founded in 1831.The Lima Army Tank Plant, built in 1941, is the sole producer of the M1 Abrams.