WebDeKalb County (/ d ə ˈ k æ b /, / ˌ d iː ˈ k æ b / də-KAB, DEE-KAB) is located in the north central portion of the U.S. 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 Decatur.