First settled in 819 by the monk Kūkai, Mount Kōya is primarily known as the world headquarters of the Kōyasan Shingon sect of Japanese Buddhism. Located on an 800-meter-high plain amid eight peaks of the mountain, which was the reason this location was selected, in that the terrain is supposed to resemble a lotus plant, the original monastery has grown into the town of Kōya.

Koya features a university dedicated to religious studies and 120 sub-temples, many of which offer lodging to pilgrims. Mount Kōya is also a common starting point to the Shikoku Pilgrimage (四国遍路, Shikoku Henro) associated with Kūkai.