Pirika Ruins located in Pirika, Imakane-cho, Setana-gun, Hokkaido is the ruins of Old Stone Age through Jomon Age. It was designated as a National Historic Site in 1994. It was discovered in 1978, when a ground survey for a dam construction was carried out. The ruin covers a huge area with 200,000 square meters that spread over the gentle hill on the left bank of the Pirikabetsu River. 190,000 stone tools with a total weight of 800 kg were excavated. Historically precious discovery of the beads made of peridotite and fatty acid of deer on the surface of a stoneware were included among them. At the present time, there is nothing but a pasture on the ruins. Visitors can see those excavated items at Pirika Old Stone Age Museum in the vicinity.