63473 -- U.S. ZIP code Municipality (1990): WILLIAMSTOWN, Missouri All ZIPs for this municipality (1990): 63473 Population (2000): 282 Housing Units (2000): 180 Land area (2000): 62.562631 sq. miles (162.036463 sq. km) Water area (2000): 0.403179 sq. miles (1.044230 sq. km) Total area (2000): 62.965810 sq. miles (163.080693 sq. km) Located within: Missouri (MO) Location: 40.246729 N, 91.773682 W