Clayton County is located in the north central portion of the U.S. state of Georgia. As of the 2020 census, the population was 297,595 by the U.S. Census Bureau. The county seat is Jonesboro. Clayton County is one of the core counties of the Atlanta metropolitan area, and it is the fifth most-populous county in the state. It is the home of most of Hartsfield–Jackson Atlanta International Airport, the busiest airport in the world by total passengers.