The highest unclimbed mountain in a particular region or in the world is often a matter of controversy. In some parts of the world surveying and mapping are still not reliable, and there are not comprehensive records of the routes of explorers, mountaineers and local inhabitants.

However, a major problem relates to the definition of a mountain. Any particular mountain, in addition to its highest point, will also have subsidiary “tops.” Generally, a subjective view is taken of what is a mountain and what is a top. The horizontal distance between main peak and top, the difference in height, the topographic prominence of the top, as well as the general topography, all come into consideration. Although objective criteria have been proposed for distinguishing “peaks” from “tops” (a prominence of 610 m, 2,000 feet is one definition), there is no widely agreed standard.

The Peakware World Mountain Encyclopedia has a list of unclimbed 7000 m Himalayan peaks which includes “tops” [1]. The list is somewhat out-of-date and is generally unreliable: for example Lhotse Middle, 8430 m, was first climbed in spring 2001. The information came from the UIAA, which also provides a list of first ascents on its Web site [2].

The mountain most widely claimed to be the highest unclimbed mountain in the world in terms of elevation seems to be Gangkhar Puensum, 7570 m (24,836 feet). It is in Bhutan, on or near the border with Tibet. In Bhutan, climbing of high mountains has been prohibited since 1994.

Since Gangkhar Puensum is off limits to climbing, a natural question is "What is the highest unclimbed non-prohibited mountain?" The answer to this is also doubtful (and as mentioned above, depends greatly on what prominence cutoff one uses). Saser Kangri II East (7,513 m, Prom=1,450 m) is a strong candidate, but access to this peak could also be dubious, since it lies near the disputed India/Pakistan border in the Kashmir area. The highest point of the Kabru massif (7,412 m (?), Prom=780 m?), south of Kangchenjunga, is reported to be unclimbed, but the names, identities and status of all of the Kabru peaks are unclear. Labuche Kang III/East (7250 m (?), Prom=570 m?), near Cho Oyu, may be another contender, but its status is hard to verify. (It is also not extraordinarily independent.)

• UIAA (use Activities, Expedition, Greater Ranges for First Ascents)
• Peakware World Mountain Encyclopedia
• Peakware World Mountain Encyclopedia: Highest unclimbed 7000 meter Himalayan peaks
• List of peaks by prominence
• List of highest mountains