Mesas & buttes (mesas are larger while buttes are smaller) are large, isolated, flat-topped protrusions of rock that jut up from a plain with steep cliffs (escarpments). They are formed by erosion of uplifted rock layers. In worldbuilding, mesas & buttes are often found in badlands and desert regions. In fantasy worldbuilding they may act like islands in a vast sand sea. They may be the sites of towns or cities and may contain underground cave systems throughout their interior. There may be cliffside pathways leading from the lower plain to the higher elevations.
When designing mesas & buttes consider how people move from the bottom to the top of these locations. Cranes, elevators, steep staircases, and more are possible.