Northeastern Japan Arc, also Northeastern Honshu Arc, is an island arc on the Pacific Ring of Fire. The arc runs north to south along the Tohoku region of Honshu, Japan. It is the result of the subduction of the Pacific Plate underneath the Okhotsk Plate at the Japan Trench. The southern end of the arc converges with the Southwestern Japan Arc and the Izu-Bonin-Mariana Arc at the Fossa Magna at the east end of the Itoigawa-Shizuoka Tectonic Line (ITIL). This is the geologic border between eastern and western Honshu. Mount Fuji is at the point where these three arcs meet. To the north, the Northeastern Japan arc extends through the Oshima Peninsula of Hokkaido. The arc converges in a collision zone with the Sakhalin island arc and the Kuril arc in the volcanic Ishikari Mountains of central Hokkaido. This collision formed the Teshio and Yubari Mountains.