Sannai-Maruyama site (三内丸山遺跡) is a Jōmon period archaeological site in Aomori, Aomori Prefecture, Japan. The site was discovered in 1992, when Aomori Prefecture started surveying a site for a planned baseball stadium. Archaeologists have used this site to further their understanding of the transition to sedentism and the life of the Jomon people. Excavation has led to the discovery of storage pits, above ground storage and long houses. These findings demonstrate a change in the structure of the community, architecture, and organizational behaviors of these people.