Mason, OH -- U.S. city in Ohio Population (2000): 22016 Housing Units (2000): 8111 Land area (2000): 17.612994 sq. miles (45.617444 sq. km) Water area (2000): 0.037241 sq. miles (0.096453 sq. km) Total area (2000): 17.650235 sq. miles (45.713897 sq. km) FIPS code: 48188 Located within: Ohio (OH), FIPS 39 Location: 39.358009 N, 84.311822 W ZIP Codes (1990): 45040 Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Mason, OH Mason