63020 -- U.S. ZIP code Municipality (1990): DE SOTO, Missouri All ZIPs for this municipality (1990): 63020 Population (2000): 20238 Housing Units (2000): 7961 Land area (2000): 148.771306 sq. miles (385.315897 sq. km) Water area (2000): 0.666409 sq. miles (1.725992 sq. km) Total area (2000): 149.437715 sq. miles (387.041889 sq. km) Located within: Missouri (MO) Location: 38.120303 N, 90.554261 W