Indus River, great trans-Himalayanriver ofSouth Asia. It is one of the longest rivers in the world, with a length of some 2,000 miles (3,200 km). Its total drainage area is about 450,000 square miles (1,165,000 square km), of which 175,000 square miles (453,000 square km) lie in the ranges and foothills of theHimalayas, theHindu Kush, and theKarakoram Range; the rest is in the semiarid plains ofPakistan. The river’s annual flow is about 58 cubic miles (243 cubic km)—twice that of theNile River and three times that of theTigris and Euphrates rivers combined. The river’s conventional name derives from theTibetan and Sanskrit name Sindhu. The earliest chronicles and hymns of the Indo-European-speaking peoples of ancient India, theRigveda, composed about 1500bce, mention the river, which is the source of the country’s name.

Physical features

The river rises in the southwesternTibetAutonomous Region ofChina nearLake Mapam at an elevation of about 18,000 feet (5,500 meters). For about 200 miles (320 km) it flows northwest, crossing the southeastern boundary of the disputedKashmir region at about 15,000 feet (4,600 meters). A short way beyondLeh, in the Indian-administeredunion territory ofLadakh, it is joined on its left by its first major tributary, the Zanskar River. Continuing for 150 miles (240 km) in the same direction into the Pakistani-administered areas of the Kashmir region, the Indus is joined by its notable tributary theShyok River on the right bank. Below itsconfluence with the Shyok, as far as theKohistan region of Pakistan’sKhyber Pakhtunkhwa province, it is fed by mighty glaciers on the slopes of theKarakoram Range, theNanga Parbat massif, and the Kohistan highlands. The Shyok, Shigar,Gilgit, and other streams carry glacial meltwater into the Indus.

TheShigar River joins the Indus on the right bank near Skardu inBaltistan. Farther downstream theGilgit River is another right-bank tributary, joining it at Bunji. A short distance downstream theAstor River, running off the eastern slope of Nanga Parbat, joins as a left-bank tributary. The Indus then flows west and turns south and southwest to enter Khyber Pakhtunkhwa province, in the process skirting around the northern and western sides of the Nanga Parbat massif (26,660 feet [8,126 meters]) ingorges that reach depths of 15,000 to 17,000 feet (4,600 to 5,200 meters) and widths of 12 to 16 miles (19 to 26 km). Trails cling grimly to precipitous slopes overlooking the river from elevations of 4,000 to 5,000 feet (1,200 to 1,500 meters).

After emerging from this highland region, the Indus flows as a rapid mountain stream between theSwat River andHazara areas in Khyber Pakhtunkhwa province until it reaches the reservoir ofTarbela Dam. TheKabul River joins the Indus just above Attock, where the Indus flows at an elevation of 2,000 feet (600 meters) and is crossed by the first bridge carrying rail and road. Finally, it cuts across theSalt Range near Kalabagh to enter thePunjab Plain.

The Indus receives its most-notable tributaries from the eastern Punjab Plain. These five rivers—theJhelum,Chenab,Ravi,Beas, andSutlej—give the namePunjab (“Five Rivers”) to the region divided between Pakistan andIndia.

Britannica Quiz

Guess the City by Its River Quiz

After receiving the waters of the Punjab rivers, the Indus becomes much larger, and during the flood season (July to September) it is several miles wide. It flows through theplain in western and southernPunjab province in Pakistan at an elevation of about 260 feet (80 meters). Because it moves so slowly across the plain, it depositsaccumulated silt on its bed, which is thus raised above the level of the sandy plain; indeed, most of the plain inSindh (Sind) province in Pakistan has been built up by alluvium laid down by the Indus. Embankments have been constructed to prevent flooding, but occasionally these give way, and floods destroy large areas. Such floods occurred in 1947, 1958, and 2010. During heavy flooding the river sometimes changes its course.

NearTatta the Indus branches into distributaries that form a delta and join the sea at various points south-southeast ofKarachi. Thedelta covers an area of 3,000 square miles (7,800 square km) or more (and extends along the coast for about 130 miles (210 km). The uneven surface of the delta contains a network of existing and abandoned channels. The coastal strip, from about 5 to 20 miles (8 to 32 km) inland, is flooded by high tides. The Indus delta has elongated protruding distributaries and low sandy beaches.

Access for the whole family!

Bundle Britannica Premium and Kids for the ultimate resource destination.

Subscribe