Jefferson -- U.S. County in Indiana Population (2000): 31705 Housing Units (2000): 13386 Land area (2000): 361.365148 sq. miles (935.931397 sq. km) Water area (2000): 1.575824 sq. miles (4.081365 sq. km) Total area (2000): 362.940972 sq. miles (940.012762 sq. km) Located within: Indiana (IN), FIPS 18 Location: 38.766912 N, 85.436056 W Headwords: Jefferson Jefferson, IN Jefferson County Jefferson County, IN