The Indo-Gangetic Plain also known as the Northern plains and the North Indian River Plain is a large and fertile plain encompassing most of northern and eastern India, the most populous parts of Pakistan, and virtually all of Bangladesh. The region is named after the Indus and the Ganges, the twin river systems that drain it. The Indo-gangetic plain is home to people of many religions, Hindus, Muslims and Buddhists.
The Indo-Gangetic plain is bound on the north by the abruptly rising 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 Vindhya- and Satpura Range, and the Chota Nagpur Plateau. On the west rises the Iranian Plateau.
The region is one of the most populated areas on Earth, being home to nearly 900 million people (or over 1/7th of the world's population).
Two narrow terrain belts, collectively known as the Terai, constitute the northern boundary of the Indo-Gangetic Plain. In the area where the foothills of the Himalayas encounter the plain, small hills known locally as ghar (meaning house in Hindi) have been formed by coarse sands and pebbles deposited by mountain streams.
Groundwater from these areas flow on the surface where the plains begin, converting large areas along the rivers into swamps. The southern boundary of the plain begins along the edge of the Great Indian Desert in the state of Rajasthan, before continuing east along the base of the hills of the Central Highlands to the Bay of Bengal. The hills vary in elevation from 300 to 1200 metres and lie on a general east-west axis.
The Central Highlands are divided into northern and southern parts. The northern part is centered on the Aravalli Range of eastern Rajasthan. In the northern part (in the state of Madhya Pradesh), the Malwa Plateau comprises the southern part of the Central Highlands and merges with the Vindhya Range to the north and south.
By another definition, the Indo-Gangetic Plain is divided into two drainage basins by the Delhi Ridge; the western part consists of the Punjab Plain and the Haryana Plain, and the eastern part consists of the Ganga-Brahmaputra drainage systems. This divide is only 300 metres above sea level, causing the perception that the Indo-Gangetic Plain appears to be continuous between the two drainage basins.
Both the Punjab and Haryana plains are irrigated with water from the Ravi, Beas, and Sutlej rivers. The irrigation projects in progress on these rivers have led to a decrease in the flow of water, which reaches the lower drainage areas in the state of Punjab in India and the Indus Valley in Pakistan. The benefits that the increased irrigation has brought to Haryana farmers are controversial, due to the effects that irrigation has had on agricultural life in the Punjab areas of both India and Pakistan.
The lower Ganga is centered in West Bengal, from which it flows into Bangladesh. After joining the Yamuna, both rivers form the Ganges Delta.
The fertile Terai region is the Nepalese extension of the Plain. The rivers encompassed are the Beas, the Chambal, the Chenab, the Ganges, the Gomti, the Indus, the Ravi, the Sutlej and the Yamuna. The soil is rich in silt, making the plain one of the most intensely farmed areas of the world. Even rural areas here are densely populated.
The main source of rainfall is the southwest monsoon which is normally sufficient for general agriculture. The many rivers flowing out of the Himalayas provide water for major irrigation works.
The region is known for the Indus Valley Civilisation and is responsible for the birth of ancient India. The flat and fertile terrain has facilitated the repeated rise and expansion of empires, including the Gupta empire, Kanauj, Magadha, the Maurya Empire, the Mughal Empire and the Sultanate of Delhi - all of which had their demographic and political centres in the Indo-Gangetic plain. During the Vedic and Epic eras of Indian history, this region was referred to as "Aryavarta" (Land of the Aryans) which was bordered on the west by the Indus and on the south by the Vindhya Mountain range. During the Islamic period, the Turkish rulers referred to this region as "Hindustan" (Land of the Hindus), deriving from the Persian term for the Indus Valley. This term was later used to refer to India in general but even into the modern era, the dialect of Hindi-Urdu spoken in this region is called Hindustani as well as the local music and culture.
There is in addition a great variety of regional languages, which in several cases form a dialect chain with one another.
The areas that are completely part or more than half part of the plains are:
Small parts of the following administrative areas are or are not part of the plain: