63303 -- U.S. ZIP code Municipality (1990): SAINT CHARLES, Missouri All ZIPs for this municipality (1990): 63301 63303 63304 Population (2000): 41659 Housing Units (2000): 16757 Land area (2000): 13.666424 sq. miles (35.395874 sq. km) Water area (2000): 0.003382 sq. miles (0.008760 sq. km) Total area (2000): 13.669806 sq. miles (35.404634 sq. km) Located within: Missouri (MO) Location: 38.762715 N, 90.539035 W