Golarion is the main world of the original Pathfinder tabletop game and is the location of the Kingmaker campaign. The blue planet is the third of dozens orbiting the sun. Like our own Earth, the planet shares a similar calendar. The planet contains vast oceans and lands with a large variety of biomes covering eight continents.
In the northern most areas are barbarians and tribal groups while the southern are governed by users of magic, undead, and ghosts. The world also includes areas with coastal pirates, devil worshipers, elves, horror and ancient tombs and more.
Pathfinder: Kingmaker primarily takes place in the northern region of Golarion on the continent of Avistan and has a mix of magic, dragons, barbarians, trolls, fey, ghosts, and more creatures. The player will tasked with building a new kingdom in this area, but how that happens and what it becomes will be totally up to the player.
See also Pathfinder Wiki - Golarion