noun
Kōshin'etsu region
A region of central Japan comprising Yamanashi, Nagano, and Niigata prefectures. Often used in weather forecasts, travel, and regional classification.
甲信越地方では明日大雪が降るでしょう。
Heavy snow is expected in the Kōshin'etsu region tomorrow.
甲信越地方の名産品を集めた物産展が開かれる。
A fair featuring local specialties from the Kōshin'etsu region will be held.
甲信越 is a shorter form often used in compounds like 甲信越地方 or 甲信越エリア. 甲信越地方 explicitly includes 地方 (region).
Compound of 甲 (Kō, from 甲斐, the old province corresponding to Yamanashi), 信 (Shin, from 信濃, the old province corresponding to Nagano), 越 (Etsu, from 越後, the old province corresponding to Niigata), and 地方 (region).