Indus (or Sinde (Sans. Sindhu, river; Pers. Ab-Sind), a river of Asia, rising on the N. side of the Himalaya, in Thibet, and discharging into the Arabian sea. Its three remotest feeders are the Senge-khabab (" sprung from the lion's mouth "), also called the Singi-choo (" lion stream "), the Lang-choo, and the Gartung-choo. All three have their sources N. of the Kailas range. The first named is the largest, and is considered the beginning of the Indus. It rises near the Kailas Parbat mountain, at an elevation of about 18,000 ft., about lat. 31° 10' N., lon. 81° 20' E., not more than 100 m. from the sources of the Sanpo, one of the principal feeders of the Brahmapootra, and of the Ganges. The Lang-choo flows into the Senge-khabab before the Gartung, and 50 m. further, flowing N. W., the river enters Ladakh. At Raldang, 100 m. from the confluence, it can still be crossed without boats during the greater part of the summer. At Ranag, 9 m. below Raldang, it is passable for horses during the whole year. The extreme width of the river at this point, however, is remarkable. The water surface, measured in summer, was 2,158 ft. across, and left nearly in the middle of the river a bank 1,155 ft. wide entirely uncovered.

It is presumed that in seasons of flood the Indus attains here a width of 3,313 ft. The depth is only 2 or 3 ft. The width of the river decreases very rapidly from this point, and about 450 m. from its source, near the city of Leh, it is reduced in the summer to 75 ft., with a depth of 8 ft. The valley of the Indus is here only 10,723 ft. high, the river having fallen nearly 5,300 ft,, or at the rate of 12 ft. to the mile. Continuing its N. TV. course through the valley S. of the Kailas range, 50 m. below the town of Kalatse it is still 75 ft. wide, but on only one third of the surface are signs of a steady flow; the remainder is either in a state of stagnation, or moves on very slowly. The river is however very deep in its main channels, measuring from 18 to 22 ft. About 55 m. below it receives the river Dras from Cashmere, and at Kiris, 47 m. further, it is joined on the right by the large river Shy-yok. At the mountain Mendok-kar, near Iskardoh, the chief town of Bulti, which the river reaches by a circuit of 50 m., it is no more than 7,255 ft. above the level of the sea.

The name Senge-khabab disappears here, and the river begins to be known as the Ab-Sind, or Indus. About 60 m. below Iskardoh it changes its course suddenly from N. TV. to S., and crosses the Himalaya a few miles above the E. end of the valley of Gilgit, from which it receives the river Yasan. It descends in a torrent to Bunji, a town 20 m. further on and only 4,870 ft. above the sea. A few miles below this it leaves the territory of Bulti and enters that of Kafiristan, through which it flows for nearly 170 m. in a tortuous S. TV. and S. course. The character of this portion of the river is almost totally unknown. It returns to the British territory at Derband, measuring in August nearly 300 ft. across, but without much depth. There are five fords between here and Attock, 60 m. below; they are at times somewhat treacherous, and it is related that at one of them, just above the influx of the Cabool, Runjeet Singh lost 7,000 men in trying to cross with his army. Although the Cabool is navigable for 40 m., the navigation of the Indus terminates just above its confluence.

Attock is situated 1,049 ft. above the sea, or 9,674 ft. below Leh. The course of the river between these two cities is 470 m. long, which shows a fall of nearly 21 ft. to the mile over this distance, or of a little more than 16 ft. to the mile from the source. From Attock to the sea the Indus is 942 m. long. It moves at first impetuously through high cliffs of slate, which contract it to a width of 250 ft., but render it 180 ft. deep. Near Kalabagh it enters a plain, takes up the Swan or Soohan, and expands again to 1,500 ft. with an average depth of 60 ft. For the next 350 m., to Mittun Kote, the Indus takes a more southerly course, and separates into numerous arms, enclosing fertile islands, which are covered during the summer inundations with an immense sheet of water, extending over the level country of the E. bank. The main channel near Kaheree is 3,000 ft. wide and 12 ft. deep. Near Mittun Kote occurs the influx of the Punjnud, which carries into it the waters of the Jhylum, Chenaub, Ravee, Beas, and Sut-lej, the five rivers of the Punjaub. The Indus swells here in its lowest stage to a width of 6,000 ft., and spreads in times of inundation over 20 m. on the W. and 10 or 12 m. on the E. side.

A S. W. course of about 50 m. carries it into the arid, rainless, alluvial plain of Sinde, where extensive irrigation works have been constructed by the British government, and others are in progress. The river has so frequently changed its direction in flowing through this region that traces of ancient channels are very numerous, the main channel being now considerably further W. than formerly. Its banks are higher than the adjacent tracts, the surface of which slopes away from the river. This peculiarity is due to the silt brought down by the waters of the Indus and deposited in consequence of the decreased rapidity of its current in this nearly level country. These silt deposits are constantly forming new land in some localities and causing the river to break through its banks in others. From Mittun Kote to the sea the Indus flows over a distance of about 450 m. The East Narra is an ancient channel which separates from it near Soodaja, and extends S. E. through the desert of Thur; it is now supplied with water by canals connecting with the Indus. The West Narra branches off 18 m. below Roree, follows a tortuous S. course of about 160 m., forms the Mantchoor lake, and returns to the Indus near Sewan, 10 m. below.

From this point the bed of the Indus is depressed 16 to 18 ft. below the adjacent lands. The Fulailee was originally a natural branch of the Indus on the E. side, returning to it about 16 m. below Hydrabad, the capital of Sinde, which is situated on the tract of land thus turned into an island. It has been converted into a main feeder for irrigation canals, S. and E. of that city. The delta of the Indus consists of numerous mouths between Hydrabad and the Arabian sea, and is about 100 m. long and 130 m. wide. The principal mouths are the Koree, the Seer, the Mooll or Maw, the Kookeewarree, the Kedy-warree, the Rechel, the Pinteeanee, and the Pittee. The last is at present the widest and deepest, and always navigable; the Hujamree was the most important till 1838, when a sudden change in the channel rendered it entirely useless. The tide rises as far as Tattah, about 70 m. from the sea. The Indus is not navigable above Roree for vessels of more than 4 ft. draught. The entire length of the Indus is about 2,000 m., and the area of its drainage basin is estimated at 312,000 sq. m.

The rise of the river commences in May, and its waters subside in the latter part of August. - The 1,700 m. of railroad now in operation through Bombay, Sinde, and the Punjaub render the Indus less important as a means of transportation than as a means of irrigation in a sultry climate where rain seldom falls. The water is very unwholesome in the early part of the inundation, and at other times it is wholesome only if kept until the earthy and vegetable admixtures subside. Fish are abundant, and form a large portion of the sustenance of the population of the adjacent country. The alligators in it are long-snouted, of the kind called gavial. In the Vedic writings the Indus is called the king of rivers, and the Ganges as well as the other streams sing praises unto it. It is generally designated in them as Sindhu, "the river." The ancient inhabitants had no more definite name for their country bordering on the Indus than Sapta Sindhavas, "the seven rivers," counting with it the Cabool and the five chief streams of the Punjaub.