The Bitter Valley is a small and lawless valley that technically lies in the purview of northern Atherdale in the Kalhastian Empire, north of the Bumblycusp and south of the northern reaches of the Dancing Peaks. It is also the source of the Firfenn River.
The valley's position between two difficult-to-navigate mountain ranges, coupled with its abundance of natural springs and fertile land, make it an easily defensible area where occupants can bunker down endlessly. The eastern end of the valley hosts the infamous Unknown, which has been historically occupied by criminal gangs and bandit kings. While the groups in the Bitter Valley have long antagonized the crown of the Empire, its relatively remote location and defensible nature have kept it relatively safe from threats of invasion from the Empire's armies, entirely due to the crown not wishing to waste the resources in taking it.
The nearby town of Petterpale is often besieged by the bandits of the Bitter Valley.