K1 to K12 Mountains: The Karakoram’s Historic Survey Peaks

🏔️ Overview

The Karakoram contains some of the highest, steepest, and most heavily glaciated mountains on Earth. Among its best-known peaks are a group identified by short survey codes: K1, K2, K3, and onward through K12.

These labels originated during nineteenth-century mapping of the Karakoram by the Great Trigonometrical Survey of India and the Survey of India. The letter K stood for Karakoram, while the numbers served as practical identifiers for distant summits whose local names were unknown, uncertain, or not yet recorded by the surveyors.

Most of the original codes were eventually replaced by geographic names. K1 became Masherbrum, K3 became Gasherbrum IV, K4 became Gasherbrum II, and K5 became Gasherbrum I. Other numbers, including K6, K7, K10, and K12, remain familiar in modern mountaineering literature.

Only K2 retained its survey code as its standard international name. Its position as the world’s second-highest mountain is a coincidence: the number 2 refers to its survey designation, not its elevation ranking.

⚡ Fast Facts

Feature	Details
Mountain system	Karakoram
Continent	Asia
Countries or territories	Primarily Pakistan, China, and the disputed India–Pakistan border region
Original survey organization	Great Trigonometrical Survey of India
Surveyor most associated with the system	Lieutenant Thomas George Montgomerie
Meaning of K	Karakoram
Initial survey period	Mid-nineteenth century
Highest K-numbered mountain	K2, 8,611 m (28,251 ft)
Lowest of K1–K12	K7, approximately 6,934 m (22,749 ft)
Codes still widely used as names	K2, K6, K7, K12 and, in historical contexts, K1–K5 and K10
Important additional designation	K3a, now identified as Gasherbrum III

🗺️ K1 to K12 at a Glance

Published elevations vary slightly among surveys, maps, and mountain databases. The figures below use commonly accepted modern elevations.

Survey code	Modern or commonly used name	Elevation	General location
K1	Masherbrum	7,821 m / 25,659 ft	Masherbrum Mountains, Pakistan
K2	K2	8,611 m / 28,251 ft	Pakistan–China border
K3	Gasherbrum IV	7,925 m / 26,001 ft	Gasherbrum massif, Pakistan
K4	Gasherbrum II	8,035 m / 26,362 ft	Pakistan–China border
K5	Gasherbrum I / Hidden Peak	8,080 m / 26,509 ft	Pakistan–China border
K6	Baltistan Peak / K6	7,282 m / 23,891 ft	Masherbrum Mountains, Pakistan
K7	K7, sometimes called Saraska Peak	6,934 m / 22,749 ft	Charakusa Valley, Pakistan
K8	Skilma Gangri / Ghursay Kangri II	About 7,422 m / 24,350 ft	Western side of the Siachen region
K9	Gamba or Gama Gangri	About 7,000 m / 22,966 ft	Karakoram; identification varies among maps
K10	Saltoro Kangri I	7,742 m / 25,400 ft	Saltoro Mountains
K11	Saltoro Kangri II	7,705 m / 25,279 ft	Saltoro Kangri massif
K12	K12	7,428 m / 24,370 ft	Saltoro Mountains

The table reflects names commonly associated with the codes in modern mountaineering references. The historic numbering was not created in one simple, uninterrupted list. Later surveys, revised maps, and competing naming systems introduced inconsistencies, especially among the designations after K5.

🧭 How the Karakoram Survey Numbers Began

In 1856, Royal Engineers officer and surveyor Thomas George Montgomerie observed the high Karakoram from a distant survey station in Kashmir. Some summits were more than 200 kilometers away, and the survey team could not immediately approach them to establish local names.

Montgomerie therefore used a regional identification system:

• K represented the Karakoram.
• A number distinguished one observed summit from another.
• The codes were working survey labels rather than elevation rankings.
• Local names were adopted when they could be reliably determined.

This approach followed a broader Survey of India policy. Surveyors generally preferred established regional names over newly invented personal or English descriptive names. Temporary codes allowed mountains to be mapped without forcing an unsupported name onto them.

The original famous sequence identified the mountains now known as Masherbrum, K2, Gasherbrum IV, Gasherbrum II, and Gasherbrum I. Survey codes were later applied to additional summits elsewhere in the Karakoram.

Were K1 to K12 all identified at the same time?

No. The familiar modern sequence combines designations from different stages of surveying and map revision.

Montgomerie’s first observations produced the best-known early codes, especially K1 through K5. Later survey work extended the system, revised mountain identifications, and introduced additional numbering. As a result, K1 through K12 should not be understood as a perfectly consistent list created during a single day or from a single viewpoint.

🏔️ The K1 to K12 Mountains

K1: Masherbrum

Elevation: 7,821 meters (25,659 feet)
Location: Gilgit-Baltistan, Pakistan
Subrange: Masherbrum Mountains

K1 is now known as Masherbrum, one of the most visually impressive mountains in the central Karakoram. It rises south of the Baltoro Glacier and dominates the approaches through the Hushe and Baltoro regions.

Masherbrum was the first major peak recorded in Montgomerie’s Karakoram sequence, which explains its original designation as K1. The number does not mean that it is the tallest mountain in the range.

Once its established name became known, the survey code was largely abandoned. Masherbrum is believed to derive from Balti, although proposed translations and interpretations vary.

The mountain was first climbed in 1960 by George Irving Bell and Willi Unsoeld during an American–Pakistani expedition. Despite its lower elevation compared with K2 and the Gasherbrums, Masherbrum is a highly technical mountain with steep rock, ice, and mixed terrain.

K2: The Survey Name That Survived

Elevation: 8,611 meters (28,251 feet)
Location: Pakistan–China border
Subrange: Baltoro Muztagh

K2 is the world’s second-highest mountain and the highest summit in the Karakoram.

It was the second prominent peak recorded in Montgomerie’s sequence. Unlike K1, surveyors did not establish a clearly accepted local name capable of replacing the code. As maps, expedition reports, and international mountaineering literature adopted “K2,” the temporary label became permanent.

The name Mount Godwin-Austen was proposed in honor of surveyor and geographer Henry Haversham Godwin-Austen, but it never replaced K2 in general usage. Regional names such as Chogori, Chhogori, and related spellings also appear, although K2 remains the internationally recognized name.

Italian climbers Lino Lacedelli and Achille Compagnoni made the first confirmed ascent on July 31, 1954. K2 is widely regarded as one of the most difficult and dangerous of the world’s 8,000-meter mountains.

K3: Gasherbrum IV

Elevation: Approximately 7,925 meters (26,001 feet)
Location: Gilgit-Baltistan, Pakistan
Mountain group: Gasherbrum massif

K3 is now known as Gasherbrum IV, an exceptionally steep and technically demanding mountain above the upper Baltoro Glacier.

Its west face is often called the Shining Wall, although the wider claim that “Gasherbrum” itself means Shining Wall is considered inaccurate. The Balti name is more closely associated with the idea of a beautiful mountain.

Gasherbrum IV was first climbed in 1958 by Walter Bonatti and Carlo Mauri during an Italian expedition led by Riccardo Cassin. Their route followed the northeast ridge.

In 1985, Wojciech Kurtyka and Robert Schauer completed a landmark alpine-style ascent of the west face. Severe exhaustion and weather prevented them from continuing to the mountain’s true highest point, but the climb became one of the most celebrated achievements in modern alpinism.

What was K3a?

K3a was the survey designation associated with Gasherbrum III, a high summit between Gasherbrum II and Gasherbrum IV.

Gasherbrum III reaches approximately 7,952 meters, although slightly different elevations appear in published sources. Because its prominence is limited, it is often classified as a subsidiary summit rather than a fully independent mountain.

K3a is important because it demonstrates that the survey system was not limited to whole-number codes. Letters could be added when surveyors needed to distinguish closely connected summits.

K4: Gasherbrum II

Elevation: Approximately 8,035 meters (26,362 feet)
Location: Pakistan–China border
Mountain group: Gasherbrum massif

K4 became Gasherbrum II, the world’s 13th-highest mountain under commonly accepted rankings.

It is one of three recognized 8,000-meter mountains associated with the wider Gasherbrum group, together with Gasherbrum I and Broad Peak. Gasherbrum II is often described as one of the more approachable 8,000-meter mountains, but that description is relative. It remains a remote expedition with avalanche hazards, crevasses, severe weather, and the physiological dangers of the death zone.

Fritz Moravec, Josef Larch, and Hans Willenpart completed its first ascent in 1956 by the southwest ridge.

K5: Gasherbrum I

Elevation: 8,080 meters (26,509 feet)
Location: Pakistan–China border
Mountain group: Gasherbrum massif

K5 is now Gasherbrum I, the highest mountain in the Gasherbrum massif and the world’s 11th-highest independent summit.

It is also known as Hidden Peak, a name introduced by explorer William Martin Conway because the mountain remains concealed behind other summits during much of the approach along the Baltoro Glacier.

Pete Schoening and Andy Kauffman reached the summit in 1958 during an American expedition led by Nicholas Clinch. Their ascent followed the route now associated with the mountain’s Roch Ridge.

Gasherbrum I later became important in the development of alpine-style Himalayan climbing. In 1975, Reinhold Messner and Peter Habeler climbed a new route without bottled oxygen and without the extensive fixed camps typical of traditional siege-style expeditions.

Was Broad Peak Given a K Number?

Broad Peak was not assigned one of the familiar original K1–K5 designations.

From Montgomerie’s distant observation point, the mountain was partly obscured by surrounding terrain, including Masherbrum. It therefore escaped inclusion in the first famous survey sequence.

This is why K3 does not mean Broad Peak. K3 is Gasherbrum IV.

K6: Baltistan Peak

Elevation: 7,282 meters (23,891 feet)
Location: Gilgit-Baltistan, Pakistan
Subrange: Masherbrum Mountains

K6, or Baltistan Peak, rises above the Charakusa and Nangmah glacier systems near the head of the Hushe Valley.

K6 is substantially lower than K2 or the Gasherbrum 8,000-meter peaks, but it possesses enormous vertical faces and dramatic relief above the surrounding valleys. Its south face rises for more than 2,000 meters and presents serious ice, snow, and mixed-climbing hazards.

An Austrian expedition first climbed K6 in 1970 after its original permit for another mountain was withdrawn. The team accepted K6 as an alternative objective and established a route from the Nangmah Glacier.

The mountain’s first ascent illustrates how expedition permits and government access decisions frequently influenced Karakoram climbing during the twentieth century.

K7: The Granite Giant of Charakusa

Elevation: Approximately 6,934 meters (22,749 feet)
Location: Charakusa Valley, Gilgit-Baltistan, Pakistan
Subrange: Masherbrum Mountains

K7 stands near the head of the Charakusa Glacier and is surrounded by some of the Karakoram’s most impressive granite walls and rock towers.

Although lower than the 7,000- and 8,000-meter giants, K7 is a formidable technical mountain. Its steep faces have attracted elite alpinists interested in difficult rock, ice, and mixed routes rather than elevation records alone.

A Japanese expedition completed the first ascent in 1984. Since then, K7 and its subsidiary summits, including K7 West, have been the setting for several important technical climbs.

Some modern sources associate K7 with the name Saraska Peak, while other references use K7 almost exclusively. Because regional naming and transliteration remain inconsistent, the survey code is still the clearest international identifier.

K8: Skilma Gangri

Elevation: Approximately 7,422 meters (24,350 feet)
Location: Western side of the Siachen region
Alternate name: Ghursay Kangri II

K8 is generally identified as Skilma Gangri, also called Ghursay Kangri II in some references.

The mountain lies in the remote eastern Karakoram, near the vast glacial systems associated with Siachen. Its location is considerably less accessible than the Baltoro region, and detailed public climbing records are limited.

K8 demonstrates one of the difficulties of researching the Karakoram survey numbers: older maps, expedition reports, and modern mountain databases may use different spellings or associate alternate names with closely grouped summits.

K9: Gamba Gangri

Elevation: Approximately 7,000 meters (about 23,000 feet)
Location: Karakoram; often placed near the Trango and Baltoro region
Alternate spellings: Gamba Gangri, Gama Gangri

K9 is one of the least clearly documented mountains in the historic sequence.

It is commonly identified as Gamba Gangri or Gama Gangri, but its precise elevation, spelling, and location are not presented consistently across modern maps and online databases. Some references place it near the Trango Towers and the Baltoro Glacier system.

Unlike K2, K6, K7, or K12, K9 did not develop a prominent international mountaineering identity. It remains primarily a historical cartographic designation.

The uncertainty surrounding K9 is a useful reminder that early survey labels did not always translate neatly into modern mountain names.

K10: Saltoro Kangri I

Elevation: 7,742 meters (25,400 feet)
Location: Saltoro Mountains, Siachen region
Subrange: Saltoro Mountains

K10 is associated with Saltoro Kangri I, the highest mountain in the Saltoro Mountains and one of the world’s highest independent summits.

Saltoro Kangri rises west of the Siachen Glacier in an extremely remote and politically sensitive part of the eastern Karakoram. The surrounding terrain contains enormous glaciers, steep ridges, high passes, and long approaches with little civilian infrastructure.

A joint Japanese–Pakistani expedition completed the first ascent in 1962 by the southeast ridge. The summit climbers were Y. Takamura, A. Saito, and Raja Bashir Ahmad.

Later military activity and access restrictions in the Siachen–Saltoro region sharply limited civilian mountaineering.

K11: Saltoro Kangri II

Elevation: Approximately 7,705 meters (25,279 feet)
Location: Saltoro Mountains
Relationship: Subsidiary summit of the Saltoro Kangri massif

K11 is commonly associated with Saltoro Kangri II, a high northern or secondary summit of the Saltoro Kangri massif.

Although it rises above many independent mountains in the Karakoram, Saltoro Kangri II is generally treated as a subsidiary summit because it is connected to Saltoro Kangri I by a high saddle and lacks sufficient prominence to qualify as a separate major mountain under common classification systems.

Its climbing history is not as clearly documented as that of the main Saltoro Kangri summit. Published mountaineering reports have described Saltoro Kangri II as an exceptionally difficult and, for long periods, unclimbed objective.

K12: The Saltoro Ultra

Elevation: 7,428 meters (24,370 feet)
Location: Saltoro Mountains, southwest of the Siachen Glacier
Prominence: Approximately 1,978 meters (6,490 feet)

K12 is one of the highest mountains whose survey designation remains its principal name.

It is the second-highest independent mountain in the Saltoro Mountains after Saltoro Kangri. Although Saltoro Kangri II is higher, that summit is usually treated as part of the Saltoro Kangri massif rather than as an independent peak.

K12 is also an ultra-prominent mountain, meaning it has at least 1,500 meters of topographic prominence.

The tragic first ascent of K12

Japanese climbers Shinichi Takagi and Tsutomu Ito reached the summit on August 30, 1974, during a Kyoto University expedition led by Goro Iwatsubo.

After reporting their successful ascent, the climbers were trapped by deteriorating weather during the descent. One climber reportedly lost a boot and crampon. Their final radio communication described the pair hanging from an ice anchor after slipping on a steep slope.

Radio contact was lost, and neither climber returned. Searchers found no trace of them, and their bodies were never recovered.

A Japanese expedition returned the following year and completed another ascent while searching for evidence of the missing climbers.

K12 was climbed from the eastern side in 1984 by an Indian Army expedition preparing for a 1985 Mount Everest expedition.

🔢 Why the Numbers Are Not Elevation Rankings

The K numbers represent survey identification, not height.

For example:

• K1 is not the highest mountain in the Karakoram.
• K2 happens to be the world’s second-highest mountain.
• K3 is lower than K4 and K5.
• K7 is lower than several mountains that never received low K numbers.
• K10 is considerably higher than K12.
• K22, associated with Saser Kangri I, is higher than several earlier-numbered peaks.

The apparent match between K2 and its global ranking as the second-highest mountain is purely coincidental.

🧩 Why the Survey Sequence Is Complicated

The K-number system appears simple, but its history is surprisingly complex.

The codes were temporary

The surveyors expected established local or geographic names to replace the codes wherever possible. This happened with Masherbrum and the Gasherbrum peaks.

The numbers came from different stages of mapping

Not every K number was assigned during Montgomerie’s first observations. Later surveyors extended and modified the system.

Closely connected peaks created confusion

The Gasherbrum massif includes several high points, leading to designations such as K3 and K3a. Similar issues occurred among the closely grouped Saltoro summits.

Names and spellings changed

Balti, Tibetan, Ladakhi, Turkic, Urdu, and other regional names were recorded using different English transliterations. The same mountain might therefore appear under several spellings.

Maps did not always agree

Survey editions, expedition maps, geographic studies, and modern databases sometimes identified the same code differently. K8 and K9 are particularly difficult to document consistently.

Political boundaries affected later exploration

Parts of the Karakoram now lie across international borders or within disputed territories. Restricted access has limited field verification and civilian exploration in several eastern areas.

🗺️ Surveying the Karakoram

The nineteenth-century surveyors worked without satellite positioning, aircraft, or modern electronic instruments. They measured distant summits using triangulation from known survey stations.

The general process involved:

1. Establishing an accurately measured baseline.
2. Building a network of known survey points.
3. Measuring horizontal and vertical angles to distant peaks.
4. Correcting for atmospheric refraction and Earth’s curvature.
5. Calculating elevations and positions through trigonometry.
6. Comparing observations from multiple stations.
7. Assigning temporary codes where names were unavailable.

The mountains’ extreme distance created substantial difficulties. Clouds, atmospheric haze, overlapping ridges, and concealed summits could all lead to incorrect identification.

Nevertheless, the surveys produced remarkably accurate early measurements and formed the foundation for modern mapping of the Karakoram.

🧗 The K Peaks in Mountaineering History

The K-numbered mountains played an important role in the development of high-altitude climbing.

K2 became one of the defining expedition objectives of the twentieth century. Gasherbrum I and II helped demonstrate lighter climbing strategies on 8,000-meter peaks. Gasherbrum IV became a test piece for elite technical alpinism.

K6 and K7 attracted climbers more interested in steep faces and difficult mixed terrain than in reaching the highest possible altitude. K10, K11, and K12 became symbols of the extraordinary remoteness and political complexity of the eastern Karakoram.

Together, the peaks illustrate the evolution of mountaineering from:

• Scientific and geographic exploration
• Large national expeditions
• Siege-style climbing with multiple camps
• Smaller international teams
• Lightweight alpine-style ascents
• Highly technical rock, ice, and mixed climbing

🏔️ Field Guide Tip

When reading an old Karakoram map or expedition report, never assume that a K number represents a mountain’s height ranking—or that the code was applied consistently across every map edition. Check the publication date, elevation, coordinates, neighboring glaciers, and alternate names before identifying the summit.

💡 Interesting Facts About the K Mountains

• K2 is the only major mountain whose temporary survey code became its standard international name.
• K1 is lower than K2, K4, and K5.
• K3 is Gasherbrum IV, not Broad Peak.
• Gasherbrum III was given the related designation K3a.
• Broad Peak was not part of the famous original K1–K5 sequence.
• Three of the K1–K12 mountains exceed 8,000 meters: K2, K4, and K5.
• K6 and K7 rise above the Charakusa and Hushe region, now famous for technical alpine climbing.
• K10 and K11 belong to the same Saltoro Kangri massif.
• K12 is an ultra-prominent mountain despite being lower than K10 and K11.
• The numbering system eventually extended far beyond K12.

❓ Frequently Asked Questions

What does the K in K2 mean?

The K stands for Karakoram. It was part of a survey identification system used during nineteenth-century mapping.

Is K2 called K2 because it is the world’s second-highest mountain?

No. It was designated K2 because it was the second major Karakoram summit recorded in that particular survey sequence. Its global elevation ranking is a coincidence.

What is K1?

K1 is Masherbrum, a 7,821-meter mountain south of the Baltoro Glacier in Pakistan.

What are K3, K4, and K5?

K3 is Gasherbrum IV, K4 is Gasherbrum II, and K5 is Gasherbrum I.

Is Broad Peak K3?

No. K3 is Gasherbrum IV. Broad Peak did not receive one of the familiar original K1–K5 designations.

Why did K2 keep its survey name?

Surveyors did not establish a local name that gained sufficient acceptance to replace the code. K2 became entrenched through maps, expedition accounts, and international usage.

Are all the K mountains in Pakistan?

No. Some stand on the Pakistan–China border, while several eastern peaks lie within the disputed Saltoro–Siachen region. However, many of the best-known survey peaks are wholly or partly within Pakistan-administered Gilgit-Baltistan.

Which K mountain is the highest?

K2 is the highest at 8,611 meters.

Which of K1 to K12 is the lowest?

K7 is generally listed at approximately 6,934 meters, making it the lowest of the commonly identified K1–K12 peaks.

Are K10 and K11 separate mountains?

K10 is Saltoro Kangri I, the main summit. K11 is commonly associated with Saltoro Kangri II, a subsidiary summit connected to it by a high saddle.

Does K12 mean the world’s 12th-highest mountain?

No. K12 is around the world’s 60th-highest independent mountain, depending on the elevation data and classification system used. The number comes from its survey designation.

🔗 Related Mountain Guides

• Karakoram
• Masherbrum — K1
• K2 — Godwin-Austen
• Gasherbrum IV — K3
• Gasherbrum III — K3a
• Gasherbrum II — K4
• Gasherbrum I — K5
• Baltistan Peak — K6
• Saltoro Kangri — K10
• K12 Mountain
• Saltoro Mountains

Sources

• The Himalayan Club — Karakoram Nomenclature — Kenneth Mason’s historical discussion of the survey system, naming policy, and later standardization of Karakoram geography. (Himalayan Club)
• ExplorersWeb — How Pakistan’s Giant Peaks Got Their “K” Names — Modern overview of the principal K-numbered mountains and their climbing histories. (Explorersweb)
• Peakbagger — K2 — Elevation, prominence, location, alternate names, and geographic data for K2. (Peakbagger)
• The Himalayan Club — The Ascent of K6, 1970 — Expedition account and geographic description of K6, or Baltistan Peak. (Himalayan Club)
• The Himalayan Club — Ascent of K12 in the Saltoro Hills — K12 elevation history, mapping notes, and the 1984 Indian Army ascent. (Himalayan Club)