The candidate sites for prisons selected by development commissioners were three locations such as the riverside of Tokachi River, the foot of a mountain in Okugoshi, Usu County (Mt. Yotei) and the upriver district of Ishikari River, and TSUKIGATA and others conducted land survey separated in three groups.
開拓使による集治監候補地は十勝川沿岸、有珠郡奥後志山麓（羊蹄山）、石狩川上流方面の三箇所で、月形らは3班に分かれ調査を行った。