Is There a Military Base in GTA IV (PS3)? No - But Military-Themed Locations Exist

No official military base exists in GTA IV. However, there are military-themed locations:

• Fort Tudor: A fortified island near Algonquin (accessible by boat) with bunkers, towers, and military props—but no active soldiers or missions.
• Military Checkpoints: Appear during certain missions/events with armed NPCs, but aren't explorable bases.

For a true base experience, look at GTA V's Fort Zancudo.