Harrison -- U.S. County in Mississippi Population (2000): 189601 Housing Units (2000): 79636 Land area (2000): 580.981237 sq. miles (1504.734433 sq. km) Water area (2000): 395.170641 sq. miles (1023.487219 sq. km) Total area (2000): 976.151878 sq. miles (2528.221652 sq. km) Located within: Mississippi (MS), FIPS 28 Location: 30.427896 N, 89.079536 W Headwords: Harrison Harrison, MS Harrison County Harrison County, MS