Hosoiri is a mountainous region nestled along the Jinzugawa River gorge. Its heart, the Inotani district, was historically a critical border checkpoint (sekisho) between the Etchu (Toyama) and Hida (Gifu) provinces. Today, the Inotani Sekishokan Museum preserves this history. The area is prized for its rugged natural beauty, hot springs, and its role as a gateway for travelers moving between the coast and the northern Japanese Alps.