The Nara Basin, also known as the Yamato Basin, is a valley in the north-western part of Nara Prefecture, Japan. It has an area of roughly 300 square kilometres (120 sq mi). It is surrounded on four sides by mountains: the Yamato Plateau in the east, the Ikoma-Kongō range in the west, the Narayama Hills in the north, and the Ryūmon Mountains in the south.