Trenton is a part of Liberty City which seems devoted entirely to business. Located near the harbour and quays on Portland, it houses a variety of warehouse businesses: from pharmaceuticals to dog food, and a multitude of shady dealings beneath.
This type of billboard map is common to many industrial estates, helping truck drivers reach the correct address amidst winding warehouse access roads. Although the resolution is too low to make out any details, it’s safe to assume that each marker relates to a different business. As the blurry “you are here” text says, this billboard has been placed on the middle-western side of the estate, at an angle to where protagonist Claude’s now-unroadworthy car is ‘parked’.
Taken while playing through the game for the first time.