Istor O Nal is the 3rd highest mountain in the High Hindu Kush range, in the Chitral District of Pakistan. It is the 68th highest independent peak in the world. It crowns a massif with 11 peaks of elevation more than 7000 m (22986ft). The peak is located a few kilometers north of Tirichmir. Because Istor o Nal is behind the highest peak of Hindukush (Tirichmir 7708m) from many view points, it is not easily visible and therefore not well known.
The word “Istor o Nal” means horse shoe in the khowar language. Istor means “horse” and nal means “shoe” and the massif is look like a giant horse shoe.
Istor o Nal was first climbed on June 8, 1955 by the Americans Major Ken Bankwala, Josef E. Murphy, Jr, and Thomas A. Mutch, on a Princeton Mountaineering Club Expedition. They climbed the west ridge, starting from the south side of the peak through the Terich Glacier. Their small, minimally financed expedition (by the standards of the time for high altitude mountaineering) achieved what was then the second highest summit attained by Americans.

The main summit 7403m was climbed by a Spanish expedition in 1969 headed by Anglada. 2 of the 11 peaks are still unclimbed i.e. North East Peak 7276m and East Peak 7100m.

In the year 2000, a Swiss Expedition led by Simon Perritaz arranged an expedition for the unclimbed North East Peak 7276m with 8 other members; they could not gain the summit due to shortage of rope, time and mostly weather condition. The two peaks are still unclimbed and an obvious challenge for mountaineers.