The Tranquil Gardens Cemetery lies slightly southeast of Darkshire in Duskwood. While the presence of many undead has made the cemetery anything but tranquil, the undead here are the weakest that you will find in Duskwood.
The first quests The Night-Watch give you involve dispatching the undead in this area. The Insane Ghoul is also located here, either inside the ruined church, or wandering about outside. Just north of the cemetery lies Blind Mary's house.