Sullivan -- U.S. County in New Hampshire Population (2000): 40458 Housing Units (2000): 20158 Land area (2000): 537.375514 sq. miles (1391.796133 sq. km) Water area (2000): 14.540379 sq. miles (37.659407 sq. km) Total area (2000): 551.915893 sq. miles (1429.455540 sq. km) Located within: New Hampshire (NH), FIPS 33 Location: 43.344206 N, 72.247327 W Headwords: Sullivan Sullivan, NH Sullivan County Sullivan County, NH