63123 -- U.S. ZIP code Municipality (1990): AFFTON, Missouri All ZIPs for this municipality (1990): 63123 Population (2000): 49680 Housing Units (2000): 22749 Land area (2000): 12.369445 sq. miles (32.036715 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 12.369445 sq. miles (32.036715 sq. km) Located within: Missouri (MO) Location: 38.549452 N, 90.325256 W