As of the 2010 U.S. Census, the most populated counties in Georgia are Fulton county, Gwinnett county, Cobb County and Dekalb County. Fulton has a population of 996,319, with Gwinnett at 877,922 , Cobb with 730,981 and Dekalb County holds 722,161 people.
A large portion of Fulton county's population lies within the city of Atlanta; this is not only the largest city in the county, but also in the entire state of Georgia. Meanwhile, Gwinnett's population is made up of a cornucopia of smaller towns, with the largest being Peachtree Corners, home to just 40,059 people, per the 2013 U.S. Census. Marietta is the largest city in Cobb county, as well as the county seat, while Dekalb County is just outside the city limits of Atlanta, with Decatur being the county seat.