Youngstown is a city in Mahoning County, Ohio, United States, and its county seat. It had a population of 60,068 at the 2020 census, makin…Youngstown is a city in Mahoning County, Ohio, United States, and its county seat. It had a population of 60,068 at the 2020 census, making it the 11th-most populous city in Ohio. The Youngstown–Warren metropolitan area had 430,591 residents in 2020. Youngstown is situated on the Mahoning River in Northeast Ohio, roughly midway between Cleveland and Pittsburgh.