Campbell (/ˈkæməl/; KAM-ǝl) is a city in Mahoning County, Ohio, United States. The population was 8,235 at the 2010 census. Campbell is served by a branch of the Public Library of Youngstown and Mahoning County. It is part of the Youngstown-Warren-Boardman, OH-PA Metropolitan Statistical Area.Campbell was formerly known as the village of East Youngstown, and this designation still appears on real estate deeds for the city. In 1922, the city was renamed for local industrialist James A.