Littered throughout both islands are 34 outposts that are controlled by the enemy. These are indicated by black smoke rising through the air, as well as a red flag on your map. Each outpost in the game is littered with a number of enemies, when all killed, will liberate that outpost and provide some benefits to you.
Every outpost in the game will usually have one or more alarms set up, which will allow enemies to call in reinforcements should they be needed. Shooting the alarm will disable that particular alarm, but if you get close enough to disable it by hand, then shutting down one alarm will shut down the rest.
For every outpost you liberate, you will receive at least 500 XP. If you clear it without the enemy raising an alarm, you get 550 XP and if you do it without being seen once, then you get 1,500 XP. In addition to the XP bonus, each outpost functions as a fast travel point, allowing you to travel around the map much more quickly.
Some outposts also have an automated shop inside the safehouse, allowing you to buy supplies or sell off excess ones. Also, liberating outposts will allow the player to unlock Path of the Hunter missions, as well as Wanted Dead quests.