Sannai-Maruyama Site, Archaeological site in Aomori, Japan.

Sannai-Maruyama is a large excavation site on a river terrace in Aomori Prefecture, where remains of a major Jomon settlement were uncovered. The grounds show reconstructed pit dwellings with post structures, covered shelters over original excavation areas, and storage buildings that offer insight into life over 5000 years ago.

The settlement emerged around 3900 BC during the Jomon period and remained inhabited for roughly 1700 years. Archaeologists began systematic excavations in 1992 after the area was planned for a baseball stadium.

The name refers to two Aomori City districts and their features: Maruyama means "circular mound" and Sannai means "three insides", after the three ravines in the area; the site is not named after people. Part of the complex lies in Yasuda, "peaceful field". Visitors can try fire-making and stone-tool making at the Jomon Jiyukan.

The site lies southwest of central Aomori, on a terrace above the right bank of the Okidate River. It is reached by the Aomori shuttle bus "Nebutan-go" from Shin-Aomori Station to the Sannai-Maruyama Iseki-mae stop, or by city bus from Aomori Station. Entry to the site and the Jomon Jiyukan is through a tunnel from the museum building, and rubber boots are lent out for walking in winter snow.

Excavators uncovered traces of more than 600 refuse pits that show how residents disposed of waste and recycled organic matter. These trash deposits contained remains of nuts, fish bones, and animal bones that reveal details about the diet of the time.