The Liberty City Port Authority are a minor law enforcement agency who operate across the states of both Liberty City and Alderney. Their headquarters are located in the Pier D, Port Tudor.
Their present extends over the Broker Navy Yard (East Hook) and the Golden Pier in Algonquin, aside of the manage of Port Tudor. They also have an exclusive jetty just north of the Alderney City Helipad.
The LCPA logo consists of three segments depicting a stray paddle boat, an anchor, and eight maritime signal flags. A rope texture appears around the segments followed by the authority title.
It is likely based on the Port Authority of New York and New Jersey (PANYNJ).
They appear to manage the Port Tudor complex, as there appear several "For Lease" signs with its logo in various buildings. All 40' containers have the logo in the cargo door, showing the control of the LCPA over the transport of goods by containers.
While the authority is mentioned in numerous locations across the map, regular LCPD officers serve in their stand-in locations including small LCPA booths along the waterfront of Algonquin. That can imply the LCPA had delegated its enforcement functions to the Liberty City and Alderney corresponding law agencies.
The flags in the upper right part of the logo shown above spell "SWIM CANT" using the maritime signal flag alphabet, likely a reference to the majority of previous characters in the Grand Theft Auto series who were unable to swim.