Henry County is located in the north central part of the U.S. state of Georgia, approximately 30 miles south of Atlanta. It is part of the Atlanta metropolitan area and covers about 323 square miles. The county seat is McDonough
. Geographically, Henry County lies mostly in the Upper Ocmulgee River sub- basin, with a small western portion in the Upper Flint River sub-basin. It is bordered by DeKalb County to the north, Rockdale County to the northeast, Newton County to the east-northeast, Butts County to the southeast, Spalding County to the southwest, and Clayton County to the west
. Key cities within Henry County include McDonough, Hampton, Locust Grove, and Stockbridge
. The county is accessible via Interstate 75, which runs through it south of Atlanta
. Notable landmarks include the Atlanta Motor Speedway and Panola Mountain State Park
