Reikwald Forest

To the south of the Empire's capital of Altdorf is the Reikwald Forest; a haven for desperadoes, cut-throats, criminals, and all manner of ne'er-do-wells. Lying between the River Reik, and the Grey Mountains, it is through this forest that the main road that links Bretonnia and the Empire runs, and those who pass along it must bring plenty of protection for their every step will be dogged by bandits and brigands. The road crosses the Grey Mountains over Axe Bite Pass, and those who emerge from the forest are very often poorer than when they entered it.

At the mouth of Axe Bite Pass is the Empire fortress of Helmgart, a massive tower that rises from the mountainside and whose battlements overlook the narrow path below. Invading armies favour Axe Bite Pass for crossing the Grey Mountains and this region of the Empire has seen many bitter battles as the armies of Reikland fight off their many enemies.

Source
pg. 108-110
 * White Dwarf #310