River in eastern Afghanistan and northwestern Pakistan.
Rising west of the city of Kabul , it flows east into Pakistan and, after a course of 435 mi (700 km), joins the Indus River northwest of Islamabad . The K 0101; bul River valley is a natural route for travel between Afghanistan and Pakistan; Alexander the Great used it to invade India in the 4th century BC. For much of its course, the river is tapped for irrigation.