Mount Jōnen is one of the 100 Famous Japanese Mountains, reaching the height of 2,857 m (9,373 ft). It is situated in Japan's Hida Mountains in Nagano Prefecture and in Chūbu-Sangaku National Park. The shape of the mountain looks like the triangle. It can be seen from Azumi Basin.

100 Famous Japanese Mountains is a book written in 1964 by mountaineer and author Kyūya Fukada. The list became famous when Crown Prince Naruhito, now Emperor, took note of it. The list has been the topic of NHK documentaries, and other hiking books. An English edition, One Hundred Mountains of Japan, translated by Martin Hood, was published in 2014 by the University of Hawaii Press (ISBN 9780824836771).