H. P. Lovecraft's influence in the Pathfinder Campaign Setting is vast and varied. His mythology can be seen in the following adventures.
- Fortress of the Stone Giants : The hounds of Tindalos can be found at Jorgenfist and later in Xin-Shalast .
- Spires of Xin-Shalast : The denizens of Leng can be encountered at the Kodar Mountains and in Xin-Shalast. The Plateau of Leng is another plane, one that overlays the Material Plane slightly in the Kodar Mountains.
- Wake of the Watcher: Old Cults, Azathoth, Nyarlathotep, Cthulhu, and a bestiary of eight Lovecraftian monsters.
Into the Darklands : The Darklands were inspired greatly by the stories "Dream Quest of Unknown Kadath", "At the Mountains of Madness" and "The Mound". The neothelids and their minions, the seugathis, worship Azathoth and Yog-Sothoth.