63124 -- U.S. ZIP code Municipality (1990): LADUE, Missouri All ZIPs for this municipality (1990): 63124 Population (2000): 9819 Housing Units (2000): 4458 Land area (2000): 8.017674 sq. miles (20.765680 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 8.017674 sq. miles (20.765680 sq. km) Located within: Missouri (MO) Location: 38.645802 N, 90.376874 W