Sidney, OH -- U.S. city in Ohio Population (2000): 20211 Housing Units (2000): 8557 Land area (2000): 10.426247 sq. miles (27.003854 sq. km) Water area (2000): 0.068340 sq. miles (0.176999 sq. km) Total area (2000): 10.494587 sq. miles (27.180853 sq. km) FIPS code: 72424 Located within: Ohio (OH), FIPS 39 Location: 40.289683 N, 84.161040 W ZIP Codes (1990): 45365 Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Sidney, OH Sidney