Niantic, IL -- U.S. village in Illinois Population (2000): 738 Housing Units (2000): 299 Land area (2000): 1.074672 sq. miles (2.783388 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 1.074672 sq. miles (2.783388 sq. km) FIPS code: 52961 Located within: Illinois (IL), FIPS 17 Location: 39.854922 N, 89.165546 W ZIP Codes (1990): 62551 Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Niantic, IL Niantic