atlanta's larger combined statistical area (csa) adds the gainesville, georgia msa, athens-clarke county, georgia msa and the lagrange, thomaston, jefferson, calhoun, and cedartown micropolitan areas, for a total 2012 population of 6,162,195. the csa also abuts the macon and columbus msas. the region is one of the metropolises of the southeastern united states, and is part of the emerging megalopolis known as piedmont atlantic megaregion along the i-85 corridor.