This thesis explores procedurally creating voxel based terrains and creating castles in them. With the explosion of interest in using voxels in games since the success of Minecraft, and even big budget titles like EverQuest Next using this technology, this research aims to address an area that has not received adequate attention: procedural generation of buildings like castles. By utilizing voxels combined with procedural generation of terrain, games like Minecraft and its many clones are able to offer worlds of near limitless size for the player to explore. However, this presents a challenge: how to fill a world with content worth exploring; primarily structures that look human-made. This project focuses on perhaps the most iconic of fantasy game structures: the castle. A voxel world engine was developed to explore this problem, complete with a procedural terrain generator similar to that used in voxel world games. The terrain generator developed for this project is capable of creating a variety of terrains randomly to test castle placement and generation. By drawing inspiration from real castles construction algorithms were developed to analyze areas of voxel terrain for good castle positioning and adaptive layout of a castle to the terrain. This was used to procedurally generate castles that aim to look as though they were placed into the world by a human agent.