Walnut, IL -- U.S. village in Illinois Population (2000): 1461 Housing Units (2000): 607 Land area (2000): 0.832855 sq. miles (2.157084 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 0.832855 sq. miles (2.157084 sq. km) FIPS code: 78526 Located within: Illinois (IL), FIPS 17 Location: 41.556404 N, 89.591503 W ZIP Codes (1990): Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Walnut, IL Walnut