Cobb County is a county in the U.S. state of Georgia, located in the Atlanta metropolitan area in the north central portion of the state. As of 2020 Census, the population was 766,149. It is the state's third most populous county, after Fulton and Gwinnett counties. Its county seat is Marietta; its largest city is Mableton.

Metro Atlanta, designated by the United States Office of Management and Budget as the Atlanta–Sandy Springs–Roswell metropolitan statistical area, is the most populous metropolitan statistical area in the U.S. state of Georgia and the sixth-largest in the United States, based on the July 1, 2023 metropolitan area population estimates from the U.S. Census Bureau. Its economic, cultural, and demographic center is Atlanta, and its total population was 6,307,261 in the 2023 estimate from the U.S. Census Bureau.