61532 -- U.S. ZIP code Municipality (1990): FOREST CITY, Illinois All ZIPs for this municipality (1990): 61532 Population (2000): 640 Housing Units (2000): 258 Land area (2000): 34.627161 sq. miles (89.683931 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 34.627161 sq. miles (89.683931 sq. km) Located within: Illinois (IL) Location: 40.357560 N, 89.823896 W