Check out these maps of Grey Mesa and the Northlands:
The campaign begins in a gnome settlement called Findleburrow. Findleburrow is as close to a city as gnome settlements get. It has a majority gnome population, with minorities of elves, satyrs, some dwarves, and other fey.
It is nestled against the Troll’s Brow mountains, in a wider region known informally as “The Northlands” by its inhabitants.
Throughout the history of Findleburrow, trolls have come down from the nearby mountains to raid and cause mayhem if they can. But the town is home to many ancient and powerful users of magic, as well as elite dwarf fighters and other defenses. For these reasons the town has been able to repel the trolls easily, until now.
The attacks have begun to increase in number, and have become more organized. The cause of this is unknown. Also, a theft has occurred which has weakened some aspect of Findleburrow’s defenses. Little is publicly known of the details of the theft.