The Pamirs are a combination of east-west and north-south ranges, with the former predominating. The east-west Trans-Alai Range, which forms the northern frame of the Pamirs, falls steeply to the intermontane Alai Valley. The high central part of the Trans-Alai, between the Tersagar Pass on the west and Kyzylart on the east, averages between 19000 and 20000 feet (5800 and 6100m), reaching its highest point at Lenin (Ibn Sina) Peak, 23405 feet (7134m). South from the Trans-Alai extend three north-south ranges. Of these the western, the Akademii (Akademiya) Nauk Range, and the central, Zulumart, are relatively short; the eastern, the Sarykol Range, forms the border between Tajikistan and China. The mountains east of the Sarykol Range are sometimes called the Chinese Pamirs.
The north-south Akademii Nauk Range extends into the northwestern Pamir system, where it rises into a huge barrier, reaching 24590 feet (7495 m) in Ismail Samani Peak (formerly Communism Peak), the highest point in the Pamirs. The eastern flank of the Akademii Nauk Range is covered on the south face by the Fedchenko Glacier. The western flank intersects other ranges that lie still farther to the west: the Peter I Range, with Moscow (Moskva) Peak (22260 feet [6785m]); the Darvaz Range, with Arnavad Peak (19957 feet [6083m]); and the Vanch and Yazgulem ranges, with Revolution (Revolyutsiy) Peak (22880 feet [6974 m]). The ranges are separated by deep ravines. To the east of the Yazgulem Range, in the central portion of the Pamirs, is the east-west Muzkol Range, reaching 20449 feet (6233m) in Soviet Officers Peak. South of it stretches one of the largest ranges of the Pamirs, called Rushan on the west and Bazar-dara, or Northern Alichur, on the east. Still farther south are the Southern Alichur Range and, to the west of the latter, the Shugnan Range. The extreme southwestern Pamirs are occupied by the Shakhdarin Range, composed of north-south (Ishkashim Range) and east-west elements, rising to Mayakovsky Peak (19996 feet [6095 m]) and Karl Marx (Karla Marksa) Peak (22067 feet [6726m]). In the extreme southeast, to the south of Lake Zorkul (Sari Qul), lie the east-west Vakhan Mountains.
It is customary to divide the Pamirs into a western area and an eastern area, distinguished by their forms of relief. In the eastern Pamirs a medium-mountain relief predominates on a high raised foundation. While the heights above sea level average 20,000 feet (6,100 metres) or more, the relative heights of the peaks above their foundation do not in most cases exceed 3300 to 5900 feet (1000 to 1800m). The ranges and massifs have mainly rounded contours, and the wide and flat-bottomed valleys and troughs between them, situated at heights of 12100 to 13800 feet (3700 to 4200m), are occupied either by quietly running, meandering rivers or by dry channels. The valleys and slopes of the ranges are covered by layers of loose material.
In the western Pamirs the relief is high-mountain and sharply disjointed, alternating between low ranges and alpine ridges capped by snow and glaciers; and there are deep, narrow ravines with high, rapid rivers. The valleys and depressions are filled with outwash debris, so that almost the only suitable places for human settlement are the alluvial fans in the valleys of tributaries of the Panj River. The transition from the eastern-Pamirs type of relief to the western-Pamirs type occurs gradually. The conventional boundary is a line joining the ridge of the Zulumart Range with Karabulak Pass in the Muzkol Range; from Pshart Pass it follows the ridge of the Northern Alichur Range to Lakes Yashil and Sarez, where it turns south to the valley of the Pamir River.