The Iwato Site (岩戸遺跡, Iwato iseki) is an archaeological site located in the Usui, Kiyokawa-cho neighborhood of the city of Bungo-Ōno, Ōita Prefecture, on the island of Kyushu,Japan.

The site consists of laters of volcanic ash deposited on top of tuff from Mount Aso, which makes stratigraphic dating accurate.

During the initial investigation, conducted in 1967, Kokeshi-shaped rock figurines estimated to be approximately 24,000 to 20,000 years old were discovered along with numerous stone tools.

Since all of the artifacts were small pieces, it was difficult to determine whether this was an aggregated tomb, but if so it would be the oldest yet found in Japan.

The site is approximately five minutes by car from Bungo-Kiyokawa Station on the JR Kyushu Hōhi Main Line.