Day -- U.S. County in South Dakota Population (2000): 6267 Housing Units (2000): 3618 Land area (2000): 1028.574329 sq. miles (2663.995168 sq. km) Water area (2000): 62.634335 sq. miles (162.222176 sq. km) Total area (2000): 1091.208664 sq. miles (2826.217344 sq. km) Located within: South Dakota (SD), FIPS 46 Location: 45.373992 N, 97.572474 W Headwords: Day Day, SD Day County Day County, SD