According to the U.S. Census Bureau , the county has a total area of 120 square miles ( 311 km² ) , of which , 59 square miles ( 152 km² ) of it is land and 62 square miles ( 160 km² ) of it ( 51.32 % ) is water.
Suffolk County , Massachusetts , has a total area of more than 300 km² of which less than 160 km² are land , and more than 155 km² is water .