There are 22 US Post Offices in Mahoning County serving a total of 194,178 residents equating to 8,826 residents per post office. It's estimated that approximately 309,930 packages are handled across the 22 county post offices annually. Mahoning County is a county located in the U.S. state of Ohio. As of the 2010 census, the population was 238,823. Its county seat is Youngstown. The county is named for an Indian word meaning \"salt lick\". Mahoning County was formed on March 1, 1846; the 83rd county in Ohio. Until 1846, the area that is now Mahoning County was part of Trumbull and Columbiana counties, when the counties in the area were redefined and Mahoning County emerged as a new county. Mahoning County is part of the Youngstown-Warren-Boardman, OH-PA Metropolitan Statistical Area."