The Indian subcontinent is a southern region and peninsula of Asia, mostly situated on the Indian Plate and projecting southwards into the Indian Ocean from the Himalayas. Geologically, the Indian subcontinent is related to the land mass that rifted from Gondwana and merged with the Eurasian plate nearly 55 million years ago. Geographically, it is the peninsular region in south-central Asia delineated by the Himalayas in the north, the Hindu Kush in the west, and the Arakanese in the east. Politically, the Indian subcontinent includes Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan and Sri Lanka.
Sometimes, the geographical term 'Indian subcontinent' is used interchangeably with 'South Asia', although that last term is used typically as a political term and is also used to include Afghanistan. Which countries should be included in either of these remains the subject of debate.
According to Oxford English Dictionary, the term "subcontinent" signifies a "subdivision of a continent which has a distinct geographical, political, or cultural identity" and also a "large land mass somewhat smaller than a continent". It is first attested in 1845 to refer to the North and South Americas, before they were regarded as separate continents. Its use to refer to the Indian subcontinent is seen from the early twentieth century. It was especially convenient for referring to the region comprising both British India and the princely states under British Paramountcy.
The term Indian subcontinent also has a geological significance. Similar to various continents, it was a part of the supercontinent of Gondwana. A series of tectonic splits caused formation of various basins, each drifting in various directions. The geological region called "Greater India" once included Madagascar, Seychelles, Antarctica and Austrolasia along with the Indian subcontinent basin. As a geological term, Indian subcontinent has meant that region formed from the collision of the Indian basin with Eurasia nearly 55 million years ago, towards the end of Paleocene.
The geographical region has historically simply been known as "India" (in antiquity referring to the Indus Valley region, not the entire subcontinent). Other related terms are Greater India and South Asia. And the terms "Indian subcontinent" and "South Asia" are sometimes used interchangeably. There is no globally accepted definition on which countries are a part of South Asia or the Indian subcontinent. The less common term "South Asian subcontinent" has seen occasional use since the 1970s.
Geologically, the Indian subcontinent was first a part of so-called "Greater India", a region of Gondwana that drifted away from East Africa about 160 million years ago, around the Middle Jurassic period. The region experienced high volcanic activity and plate subdivisions, creating Madagascar, Seychelles, Antarctica, Austrolasia and the Indian subcontinent basin. The Indian subcontinent drifted northeastwards, colliding with the Eurasian plate nearly 55 million years ago, towards the end of Paleocene. This geological region largely includes Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan and Sri Lanka. The zone where the Eurasian and Indian subcontinent plates meet remains geologically active, prone to major earthquakes.
The English term "subcontinent" mainly continues to refer to the Indian subcontinent. Physiographically, it is a peninsular region in south-central Asia delineated by the Himalayas in the north, the Hindu Kush in the west, and the Arakanese in the east. It extends southward into the Indian Ocean with the Arabian Sea to the southwest and the Bay of Bengal to the southeast. Most of this region rests on the Indian Plate and is isolated from the rest of Asia by large mountain barriers.
Using the more expansive definition – counting India, Pakistan, Bangladesh, Sri Lanka, Nepal, Bhutan and Maldives as the constituent countries – the Indian subcontinent covers about 4.4 million km2 (1.7 million sq mi), which is 10% of the Asian continent or 3.3% of the world's land surface area. Overall, it accounts for about 45% of Asia's population and over 25% of the world's population, and it is home to a vast array of peoples.
The Indian subcontinent is a natural physical landmass in South Asia, geologically the dry-land portion of the Indian Plate, which has been relatively isolated from the rest of Eurasia. Given the difficulty of passage through the Himalayas, the sociocultural, religious and political interaction of the Indian subcontinent has largely been through the valleys of Afghanistan in its northwest, the valleys of Manipur in its east, and by maritime routes. More difficult but historically important interaction has also occurred through passages pioneered by the Tibetans. These routes and interactions have led to the spread of Buddhism out of the Indian subcontinent into other parts of Asia. And the Islamic expansion arrived into the Indian subcontinent in two ways, through Afghanistan on land and to Indian coast through the maritime routes on the Arabian Sea.
Whether called the Indian subcontinent or South Asia, the definition of the geographical extent of this region varies. Geopolitically, it had formed the whole territory of Greater India. In terms of modern geopolitical boundaries, the Indian subcontinent comprises the Republic of India, Pakistan, Bangladesh, Nepal, Bhutan, besides, by convention, the island nation of Sri Lanka and other islands of the Indian Ocean, such as the Maldives. The term "Indian continent" is first introduced in the early 20th century, when most of the territory was part of British India.
The Hindu Kush, centered on eastern Afghanistan, is the boundary connecting the Indian subcontinent with Central Asia to the northwest, and the Persian Plateau to the west. The socio-religious history of Afghanistan are related to the Turkish-influenced Central Asia and northwestern parts of the Indian subcontinent, now known as Pakistan. Others state Afghanistan being a part of Central Asia is not an accepted practice, and it is "clearly not part of the Indian subcontinent".
This list includes dependent territories within their sovereign states (including uninhabited territories), but does not include claims on Antarctica. EEZ+TIA is exclusive economic zone (EEZ) plus total internal area (TIA) which includes land and internal waters.