From the introduction:
The adventure starts in the trading town of Kelna, in the northeastern part of Troyso, but the main action takes place farther north in the Mountain Dwarf fortress of Den Tharum, built into the side of Mount Brurdar.
Kelna is a medium-sized town built mainly of granite sitting in the foothills of the Shauram Mountains. The surrounding countryside is mostly pine forests. The full-time population is mostly Humans and Hill Dwarfs, but on a busy market day you can see folks from all over the continent. Anyone who wants Dwarven-forged goods out of Den Tharum comes to Kelna to buy and trade.
The Mountain Dwarves of Den Tharum are extremely reclusive, even shunning their cousins, the Hill Dwarves. They only travel to the trade town to sell their wares, and the rest of the time is spent inside the mountain, behind two sets of giant metal doors.