The Tokachi Horokayanto pit dwellings are a large indigenous settlement stretching about 2km from north to south on a 15m-high Bansei coastal terrace facing the Pacific Ocean, with over 130 pit dwellings scattered around the area. Relics include mostly Satsumon-style pottery, with a few obsidian stone tools excavated along with the pottery. Other finds include a stone weight made from slightly processed natural stone that is thought to have been used for fishing, numerous pebbles that are thought to have been used as weights for straw mats, corroded pieces of iron that are thought to be fragments of metal tools, and animal skeletons.

What is unique about this site is that only a small number of pottery and stone tools have been unearthed, and metal tools have been unearthed, which has also drawn attention. It is believed that during the Satsumon culture period, the use of stone tools had already fallen into disuse, and metal and wooden tools were widely used. These historic sites were registered as a Hokkaido designated historic site on July 7, 1966.