dekalb_county,_georgia | largestcity | dunwoody,_georgia <tsp> atlanta | ispartof | dekalb_county,_georgia <tsp> atlanta | country | united_states <tsp> atlanta | ispartof | georgia <sep> dekalb county (,  də-kab, dee-kab) is located in the north central portion of the us state of georgia as of the 2020 census, the population was 764,382, making it georgia's fourth-most populous county its county seat is decaturdekalb county is included in the atlanta-sandy springs-roswell, ga metropolitan statistical area it contains roughly 10% of the city of atlanta (the other 90% lies in fulton county) 
atlanta is part of delkalb county (largest city is dunwoody). georgia. united states.dekalb county georgia is georgia's fourth-most populous county