Kosuge is located in the mountainous far northeastern corner of Yamanashi Prefecture. The municipality consists of eight hamlets of Hashidate, Kawaike, Tadamoto, Nakagumi, Tobu, Shirasawa, Konagata, Nagasaku. The seven villages from Hashidate to Konagata are along the Kobuchi River in the Tama River water system, and the Nagakushi village is along the Tsurugawa River in the Sagami River water system. The hamlets have elevations between 540 and 780 meters. Forest occupies 95% of the total area of the village, with 30% protected
watershed forest within the
Chichibu Tama Kai National Park, providing water for the
Tokyo Metropolis.
Neighboring municipalities Tokyo metropolis: •
Okutama Yamanashi Prefecture: •
Kōshū •
Otsuki •
Tabayama •
Uenohara Climate The village has a climate characterized by characterized by hot and humid summers, and relatively mild winters (
Köppen climate classification Cfa). The average annual temperature in Kosuge is 8.9 °C. The average annual rainfall is 1552 mm with September as the wettest month. The temperatures are highest on average in August, at around 22.1 °C, and lowest in January, at around -2.2 °C. ==Demographics==