the counties listed below are included in the atlanta–sandy springs–gainesville csa. (bold counties are also in the somewhat smaller atlanta–sandy springs–roswell msa.) however, most other entities define a much smaller metropolitan area by including only the counties which have the densest suburban development. fulton, dekalb, gwinnett, cobb, and clayton were the five original counties when the atlanta metropolitan area was first defined in 1950, and continue to be the core of the metro area. these five counties along with five more (cherokee, douglas, fayette, henry and rockdale) are members of the atlanta regional commission, a weak metropolitan government agency which also is a regional planning agency. the ten arc counties and five more (bartow, coweta, hall, forsyth, paulding) form part of the metropolitan north georgia water planning district, created in 2001.