The Tokachi Horokayantou Pit Group is a large aboriginal residential settlement built on a 15-meter-high late-successional coastal terrace facing the Pacific Ocean, extending approximately 2 km from north to south, with more than 130 sites in the surrounding area. The site is mainly composed of rubble earthenware, and a small number of obsidian stone tools have been excavated along with the earthenware, as well as stone weights made from natural stone, many small stones that were probably used as weights for seat weaving, corroded iron fragments that were probably fragments of metal tools, and animal skeletons.

This site is characterized by the small number of earthenware and stoneware and the presence of metalware, and the excavation of Okhotsk-style earthenware is also noteworthy. It is believed that probably by the time of the Abravation Culture, the use of stone tools had already been discontinued and metal and wood tools were widely used. These historic sites were registered as Hokkaido-designated historic sites on July 7, 1966.