Fetching details from the dictionary...
mountain district
険しい山岳地帯をようやく越えた。
We finally crossed the rugged mountainous region.
救助隊は山岳地帯で捜索活動をした。
The rescue team conducted search operations in the mountainous region.
山岳地帯に住む人々は古くからの伝統を守る。
People living in mountainous regions preserve their ancient traditions.