The Ena (Japanese恵 那 山, san ) is a mountain in the Kiso Mountains in Gifu Prefecture on the main Japanese island of Honshu. He is 2189.8 meters high. The pyramidal Ena -san rises above the valley of Nakatsugawa. One of the longest road tunnel in Japan (8.4 miles) runs under the Ena. From Nagoya you can reach the mountain in about 1.5 hours.