The Free Zone or Liberated Territories is a term used by the Polisario Front government of the Sahrawi Arab Democratic Republic, a partially recognized sovereign state in the western Maghreb, to describe the part of Western Sahara that lies to the east of a 2,200-kilometre border wall flanked by a minefield, often referred as the Berm, and to the west and north of the borders with Algeria and Mauritania, respectively. Wikipedia