The Indo-Gangetic Plain, also known as Indus-Ganga and the North Indian River Plain, is a 255 million hectare (630 million acre) fertile plain encompassing most of northern and eastern India, the eastern parts of Pakistan, and virtually all of Bangladesh. The region is named after the Indus and the Ganges, and encompasses a number of large urban areas. The Indus-Ganga plain is bound on the north by the Himalayas which feed its numerous rivers and are the source of the fertile alluvium deposited across the region by the two river systems. The southern edge of the plain is marked by the  Chota Nagpur Plateau. On the west rises the Iranian Plateau.