61477 -- U.S. ZIP code Municipality (1990): SMITHFIELD, Illinois All ZIPs for this municipality (1990): 61477 Population (2000): 775 Housing Units (2000): 327 Land area (2000): 52.450365 sq. miles (135.845817 sq. km) Water area (2000): 0.032353 sq. miles (0.083794 sq. km) Total area (2000): 52.482718 sq. miles (135.929611 sq. km) Located within: Illinois (IL) Location: 40.500643 N, 90.315769 W