Portland Rock is a small island within the boundaries of Portland Beach, Liberty City. The rock also contains a lighthouse. The Portland Rock appears in the final mission of Grand Theft Auto: Liberty City Stories, The Sicilian Gambit. In Grand Theft Auto III a mission Gone Fishing takes place in the vicinity of the Portland Rock.
In GTA Liberty City Stories, the rock contains a small dock and a stairway leading up to the lighthouse from the dock, as well as various trees and shrubbery scattered about the island. However, in GTA III, Portland Rock is completely barren and devoid of any vegetation. Also, in GTA III, the stairway and dock are absent, possibly due to a storm or because of improper maintenance. The rock is unreachable in GTA III. If the player manages to reach it, he will be forced to slide down the island and in to the water.
- One way to get up to the lighthouse in the PC version of GTA III is to take a boat to the island, turn your back towards the island and then jump up the island backwards.
- The PC and Playstation 2 versions of GTA III have a broken texture making the lighthouse white and grey, but it is actually supposed to be red like GTA: Liberty City Stories. You can still see the red texture of the lighthouse by looking at it from the docks south of the lighthouse. This was fixed in the Xbox version of GTA III.