There are 4 Bandit Camps in Dying Light 2. Finding and clearing all Bandit Camps unlocks the "Ban Hammer" achievement / trophy.
To take over a bandit camp, you need to kill the Gang Leader, eliminate his Lieutenants, and then claim the Camp Flag Tower. When you claim the camp, you'll establish a safe zone and earn additional rewards: XP, weapons, outfits, etc.
Jack & Joe's Camp (1)Rewards: 1,500 Combat XP, 500 Parkour XP, Regeneration Booster. The liberation of this camp is an objective of the main story quest "The Raid".
Jack & Joe's motley crew use this as their base from which they terrorize the local population. Eliminating this bandit camp will make the neighborhood much safer.
Downtown Thugs (3)Rewards: 3,000 Combat XP, 1,000 Parkour XP, The Sign (3 - Artifact 2H Axe).
Local gang formed by insurance brokers and leverage experts supported by some IT specialists. Eliminating this bandit camp will make the neighborhood much safer.
Garrison Heights (4)Rewards: 3,750 Combat XP, 1,250 Parkour XP, Railing (4 - Artifact 2H Hammer).
The highest-postioned bandit camp in the world. This statistic would be in a record book if they were still being published. Eliminating this bandit camp will make the neighborhood much safer.
Heron Renegados (6)Rewards: 5,250 Combat XP, 1,750 Parkour XP, Motorhead (6 - Artifact 2H Mace).
Renegade chapter founded by Paulo Garcia. He died a few years ago but the Spanish name stayed. Eliminating this bandit camp will make the neighborhood much safer.