Hinesville is a city in the U.S. state of Georgia and is located on the Atlantic coastal plain. The county seat of Liberty County, it had a pop…Hinesville is a city in the U.S. state of Georgia and is located on the Atlantic coastal plain. The county seat of Liberty County, it had a population of 34,891 at the 2020 U.S. Census. It is the principal city of the Hinesville metropolitan area, which comprises all of Liberty County, including the Fort Stewart army installation, plus neighboring Long County.