Highest unclimbed mountain

An unclimbed mountain is a mountain peak that has not been climbed to the top. Determining which unclimbed peak is highest is often a matter of controversy. In some parts of the world, surveying and mapping are still unreliable. There are no comprehensive records of the routes of explorers, mountaineers, and local inhabitants. In some cases, even modern ascents by larger parties have been poorly documented and, with no universally recognized listing, the best that can be achieved in determining the world's highest unclimbed peaks is somewhat speculative. Most sources indicate that Gangkhar Puensum (7570 m) on the Bhutan–China border is the tallest mountain in the world that has not been fully summited. Gangkhar Puensum has been off limits to climbers since 1994 when Bhutan prohibited all mountaineering above 6000 m due to spiritual/religious beliefs.

Unclimbed mountains are sometimes referred to as "virgin peaks". Many virgin peaks exist because no one has had access to that mountain due to its geographic isolation or political instability. Some are off limits due to religious beliefs in that country or region which hold that a certain mountain is sacred and should remain inviolate. Of those, Mount Kailash, a mountain in the Ngari Prefecture, Tibet Autonomous Region of China, with an altitude of 6638 m is one of the most prominent. It lies in the Kailash Range (Gangdisê Mountains) of the Transhimalaya, in the western part of the Tibetan Plateau. Mount Kailash is considered sacred in four religions: Hinduism, Buddhism, Jainism and Bon. Because of its status as a sacred mountain there are annual pilgrimages to see it, but setting foot on it is forbidden.

Additionally, since climbing tall mountains is usually a major undertaking and climbers are attracted to climbing the tallest ones, lower peaks (even if they are very formidable) simply get less attention, and instead the taller peaks are summited again, by parties following a new route, or perhaps during the winter when conditions are generally more treacherous.

Definition of a mountain
Many mountains, in addition to their highest point or peak, also have subpeaks. There is no universally accepted way of deciding when a subpeak is distinct enough to be classified as a mountain in its own right; therefore, any list of the world's mountains is subject to dispute. The topographic prominence of each apex and the general topography of the area both come into consideration when determining their status. Although objective criteria have been proposed, there is no widely agreed standard. In 1994, the International Climbing and Mountaineering Federation classified 82 mountain peaks in the Alps whose summits were at least 4000 m above sea level and with at least 30 m of topographic prominence over any adjacent mountain pass or col, as a distinct peak.

Verification of unclimbed status
It can be difficult sometimes to determine whether or not a mountain peak has been fully summited. Long before modern mountaineering commenced in the middle of the 19th century, evidence indicates that people did indeed travel up to the summits or near to the summits of major mountain peaks. Archaeological excavations in the Andes have shown that humans traveled up to 6739 m in prehistoric times. Permanent settlements as high as 4500 m were established as far back as 12,000 years ago in the Andes. In the Greater Himalaya region, Lhasa, in Tibet, sitting at 3650 m has been permanently occupied since the 7th century and many smaller settlements across the Greater Himalaya thrive at elevations exceeding 4000 m. With humans living at high elevations for many millennia, nearby peaks to such settlements may or may not have been summited at some point in the past. However, many regions away from settlements may never have been explored, especially since some high peaks in the Greater Ranges are so remote that they were unknown to local inhabitants until they were sighted by explorers.

The world's third-tallest peak, Kangchenjunga, has been summited a number of times, but on the 1955 expedition the first climbers of the peak agreed to honor the wishes of locals and not set foot on the topmost part of the mountain. Succeeding mountaineering parties may (or may not) have followed this tradition. Similarly, Nanda Devi has also been climbed but the topmost summit was not ascended and the primary summit is now off limits to climbers. Machapuchare had only one summit attempt back in 1957 when climbers came within 150 m of the summit; Nepal then banned future attempts.

Gangkhar Puensum
The mountain most widely claimed to be the highest unclimbed mountain in the world in terms of elevation is Gangkhar Puensum (7570 m). It is in Bhutan, on or near the border with China. In Bhutan, the climbing of mountains higher than 6000 m has been prohibited since 1994. The rationale for this prohibition is based on local customs that consider this and similar peaks to be the sacred homes of protective deities and spirits, and the lack of high-altitude rescue resources from any locale closer than India. The prohibition was further expanded in 2003 when mountaineering of any kind was disallowed entirely within Bhutan. Gangkhar Puensum will likely remain unclimbed so long as the government of Bhutan prohibits it.

Highest unclimbed non-prohibited peak
It is unclear which is the highest unclimbed non-prohibited mountain. While some recognize only peaks with 100 m of topographical prominence as individual summits, the International Climbing and Mountaineering Federation uses a 30 m cutoff for determining individual summits. Unclimbed summits include one on the massif known as Kabru (7318 m prominence c. 100 m), Labuche Kang III/East (7250 m) with prominence of 570 m and Karjiang (7221 m with a prominence of 895 m).

Most prominent unclimbed peak
Unclimbed candidates with high topographic prominence are by definition independent mountains, but some have relatively modest elevations. With such peaks, there is a greater possibility of undocumented ascents, perhaps occurring long ago.

As of mid-2014 Sauyr Zhotasy (3840 m, prominence of 3252 m), the high point in the Saur Range on the border between Kazakhstan and China, and Mount Siple (3110 m, prominence of 3110 m) on Siple Island off the coast of Antarctica, have no record of successful ascents. The unclimbed status of each of these peaks is difficult to confirm, although Mount Siple in particular is remote, uninhabited (and without any nearby habitation), and seldom visited. The most recent summiting of a formerly unclimbed most prominent mountain (with a prominence of 12,169 ft) was in June 2014 in the Finisterre Range of Papua New Guinea.

List of highest unclimbed peaks
The following peaks, with a minimum prominence of 150 m, were thought to be unclimbed.

Mountains with prominence over 300 m in bold.