The Linnorm Kingdoms
Blackraven Hall is a fortress constructed for the sole purpose of monitoring the eastern border of the Lands of the Linnorm Kings from the monstrous creatures in neighbouring Irrisen. It is the largest fortress in the nation, and overlooks the Rimeflow River.
Built in 3314 AR, Blackraven Hall was always intended as a bulwark against the forces of the Baba Yaga. Constructed atop the foundations of a Thassilon pyramid, the fortress is an enormous granite defense, filled with numerous underground chambers and strange magical resources. These ancient powers (including bound golems and controlled outsiders) have proven invaluable to the defense of Blackraven Hall time and time again, especially against the vile witch magic that could have slain the human defenders with ease.
As befitting the name of the fortress, the organisation known as the Blackravens are responsible for its defense. Their leader, Freyr Darkwine, has spent the last decade improving the already formidable defenses by orchestrating the excavation of a moat, the building of spike-filled ditches and other obstacles designed to hinder attackers. Several river drakes have allied themselves with the Blackravens, inhabiting the moat and strengthening the defenses even further.
Blackraven Hall monitors trade carefully between the two nations, enforcing heavy tolls on trade using the river. The fortress accepts refugees from Irrisen but typically imprisons them for several days, weeks or longer before deciding whether the newcomer is friend or foe.
[Blatantly copied and pasted from http://www.pathfinderwiki.com/wiki/Blackraven_Hall]
(Interior of keep not precisely to scale.)