United States National Guard
The National Guard had its own "territory" by some warehouses in Ocean Docks, Los Santos. There they stored weaponry. In the mission Robbing Uncle Sam, Ryder and CJ managed to break through the fences and steal some weapons. In the mission when the player gains a six star wanted level the National Guard will give chase in Barracks OLs and Rhinos. It is assumed that this is the state of San Andreas own "division" of the National Guard.