Whether they are knights of chivalrous causes or nobles scheming nefarious designs, the movers and shakers of Golarion need strongholds to host their forces and to serve as a headquarters for launching their various plots and goals. Perhaps no strongholds are more suited to this challenge than the mortar-and-stone castles, keeps, and fortresses that dot the world, whether they are entrenched on grassy baileys or built into the sides of sheer mountain ranges. Castles of the Inner Sea provides a thorough exploration of six different castles set throughout the Inner Sea region of the Pathfinder campaign setting. Detailed descriptions of the castles examine their histories as well as their most important features and structures, breathing life into fully realized maps of the castle grounds. Rundowns of castle denizens and stat blocks for key NPCs give players reasons to fear the dangers of these soaring fortifications, and a sample adventure location for each castle makes it easy for Game Masters to drop castle encounters into any game.