Iroquois -- U.S. County in Illinois Population (2000): 31334 Housing Units (2000): 13362 Land area (2000): 1116.427566 sq. miles (2891.534000 sq. km) Water area (2000): 1.602792 sq. miles (4.151211 sq. km) Total area (2000): 1118.030358 sq. miles (2895.685211 sq. km) Located within: Illinois (IL), FIPS 17 Location: 40.749055 N, 87.833796 W Headwords: Iroquois Iroquois, IL Iroquois County Iroquois County, IL