The Liberty City Port Authority (LCPA) in the HD Universe, is responsible for all waterways and ports of Liberty City in Grand Theft Auto IV, The Lost and Damned and The Ballad of Gay Tony. They use the same uniforms and vehicles as the Liberty City Police Department. Their jurisdiction is Port Tudor, Alderney.
Protecting the ports and waterways of Liberty City is their mission. Making sure that the people of Liberty City are safe from harmful threats such as terrorism. Drug trafficking, human trafficking, arms dealing and protecting the areas near the water from litter and speeding boats. They are also responsible for the maintaning of the piers and docks located all around Liberty City. Many of their booths can be found all around port areas densly populated with people.
If the player is arrested by a Port Authority officer they will be processed at the nearest precinct. Just like regular police officers if killed the player automatically gets three stars.
Locations of LCPA booths and officers are in areas of Westminster near Golden Pier the booth is located at the Golden Pier and across the street. Another location is near the dock where the mission Babysitting is started from. The sign reads all information on them. They can also be found patrolling in helicopters and in police Predator boats.