Mount Senjō, Mountain summit in Akaishi range, Japan.

Mount Senjō is a 3,033 m peak at the northern end of the Akaishi range, on the border of Ina in Nagano and Minami-Alps in Yamanashi. Its summit stands above three cirques: Kosenjō to the east, Yabusawa to the north and Daisenjō to the southeast. The upper slopes are dark green with a pale, bare patch and grey rock near the crest; the west face is steep, while the other sides are gentler. The mountain is built of hard sandstone, slate and chert of the Akaishi Group.

In 1909 Kawada Moku climbed the peak and recorded three stone monuments at the top, inscribed with names such as Maedake Sanchū Daijin; they no longer exist. On 19 March 1925 Nishibori Eizaburō and three companions from Kyoto's Three High Mountain Club made the first winter ascent. In 1930 Takezawa Chōei built the Nagasawa-sō hut at Kitazawa Pass, and in 1980 the Minami Alps forest road opened, bringing bus services and many more climbers.

The name is written 仙丈ヶ岳, sometimes 千丈ヶ岳 in Edo-period gazetteers; 丈 is a unit of length, and the name is thought to liken the mountain's height to roughly 1,000 jō. Another explanation derives it from the thousand-mat width of the summit cirque. On the ridge between the summit and Kosenjō-dake stands a stone monument to climbers who died on the mountain.

Hikers approach the mountain via Kitazawa Pass, which provides two mountain huts and camping spots for overnight stays during the climbing season. Good physical preparation is needed before attempting the ascent, and timing your visit during peak seasons makes the journey safer and more comfortable.

The summit offers a view of Japan's five highest peaks—Fuji, Kita-dake, Ai-no-take, Hotaka and Yari-ga-take—and of all three of the country's volcanoes above 3,000 m: Fuji, Ontake and Norikura. A memorial stone for climbers who died stands on the ridge between the summit and Ko-Senjō-dake.