The Drakalor Chain is one of the many places in the world of Ancardia. It is the location where the game is set. Every game of ADOM is limited to this location (unless the player is pursuing an ultra ending in which case the PC will have to venture to the Chaos plane). It is a large valley full of varied terrain types and magically formed dungeons that is entirely encircled by high mountains. Only a small pass in the very north-east corner of the chain allows access to the area and is the very location where each PC starts the game.
The Locations page lists all places of interest within the Drakalor Chain.
Note that the PC will need to travel through the Drakalor Chain and the valley itself is the game location commonly referred to as the wilderness.