Omiyama site is a settlement from the Middle Jomon Period (c. 3,500?2,500 BC) located at an altitude of 1,300 meters. This site is the only archaeological settlement discovered at a location higher than 1,100 meters above sea level and it was designated a National Historic Site in 1966. The excavation revealed 50 pit dwellings along with many pottery vessels and stone tools. This site became a historic park and two reconstructed pit dwellings are located there. Artifacts from this site are stored and exhibited at the Kawakami Village Culture Center.