The city of Tucker was incorporated in 2016 as Atlanta 's metropolitan area .
Six cities – Johns Creek ( 2006 ) , Milton ( 2006 ) , Chattahoochee Hills ( 2007 ) , Dunwoody ( 2008 ) , Peachtree Corners ( 2012 ) , and Brookhaven ( 2012 ) – have incorporated since then , following the lead of Sandy Springs in 2005.The Atlanta metropolitan area was first defined in 1950 as Fulton , DeKalb , Gwinnett , Cobb and Clayton counties .