The distribution of rich clusters of galaxies in the new southern catalog of ACO (Abell, Corwin, and Olowin) is examined. A comparison with the cluster distribution in the northern Abell catalog, published in 1958, is presented. The similarities as well as the differences between the catalogs are highlighted. The angular cluster correlation function of the ACO catalog is consistent with the Abell cluster correlation, showing strong superclustering to ~50h^-1^ Mpc. The correlation amplitude scales with depth as expected for real spatial clustering. Plate-to-plate variation effects are investigated; no significant impact of the latter on the cluster correlation is observed.