Territories are one of the most important things in gangwars. The goal of the territory system is to takeover parts of the town to gain XP and money rewards for your Gang. The Gang will only get these rewards if all capture point of the Territory are captured. The more capture points the territory has, the higher are the rewards.
There are 4 territores on gw_downtown_v3:
If you enter a territory you will see the name of the territoy and how many points you own on your HUD.