Turners Island is a privately owned, 14 acre marine-rail cargo terminal located on the South Portland side of Portland Harbor in Southern Maine. The terminal handles any product that is shipped either by rail or sea, and provides heavy lift, and marine construction services. There is a short-rail line connecting the terminal to a 188 acre open storage site, numerous industrial companies, and a spur from Guilford Railroad, which provided rail access to points in the north, south, and west. Turner's Island has 10,000 square feet of dry storage.

Turners Island is equipped with a roll-on-roll-off ramp for marine-marine or marine-rail transfers. Presently the terminals wharf is being reconstructed, with work to be completed this year. Upon completion, the terminal will be able to accommodate vessels up to 500 feet in length with a MLW draft of 25 feet. Currently there are three cranes at the terminal, two having 65-long ton capacities, and the third with a 130-long ton capacity. Construction of a fourth crane will be completed this year. The new crane will be barge mounted, 500-long ton capacity, and will be contracted to other Port facilities. This will give the Port of Portland an added competitive advantage and increase it's heavy lift capacity.