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 all or part of 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 the 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 was especially convenient for referring to the region comprising both British India and the princely states under British Paramountcy. Though the English term "subcontinent" mainly refers to the Indian subcontinent from early 20th century, the term was earlier attested in 1845 to refer to the North and South Americas, before they were regarded as separate continents. The geopolitical definition and the use of terms such as Indian subcontinent, South Asian subcontinent and South Asia is a contested topic.
The region has been variously labelled as "India" (in its pre-modern sense), Greater India, the Indian Subcontinent (a term in particularly common use in the British Empire and its successors) and South Asia. Though the terms "Indian subcontinent" and "South Asia" are generally used interchangeably, some academics hold that the term "South Asia" is the more common usage in Europe and North America. According to historians Sugata Bose and Ayesha Jalal, the Indian Subcontinent has come to be known as South Asia "in more recent and neutral parlance." Indologist Ronald B. Inden argues that the usage of the term "South Asia" is becoming more widespread since it clearly distinguishes the region from East Asia.
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 Indian subcontinent has been a term particularly common in the British Empire and its successors. Historians Catherine Asher and Cynthia Talbot state that the term "Indian subcontinent" describes a natural physical landmass in South Asia that has been relatively isolated from the rest of Eurasia. According to Mittal and Thursby, it has also been labelled as India (in its classical and pre-modern sense), Greater India, or as South Asia. The BBC and some academic sources refer to the region as the "Asian Subcontinent". Some academics refer to it as "South Asian Subcontinent".
According to anthropologist John R. Lukacs, "the Indian Subcontinent occupies the major landmass of South Asia", while the political science professor Tatu Vanhanen states, "the seven countries of South Asia constitute geographically a compact region around the Indian Subcontinent". According to Chris Brewster, India, Pakistan, Bangladesh, Sri Lanka, Nepal and Bhutan constitute the Indian subcontinent; with Afghanistan and Maldives included it is more commonly referred to as South Asia. The geopolitical boundaries of the Indian subcontinent, according to Dhavendra Kumar, include "India, Pakistan, Bangladesh, Sri Lanka, Nepal, Bhutan and other small islands of the Indian Ocean". The Maldives, a country consisting of a small archipelago southwest of the peninsula, is considered part of the Indian subcontinent.
The precise definition of an "Indian subcontinent" as opposed to "South Asia" in a geopolitical context is somewhat contested. There is no globally accepted definition on which countries are a part of South Asia or the Indian subcontinent. While Afghanistan is not considered as a part of the Indian subcontinent, Afghanistan is often included in South Asia. Similarly, Myanmar is included by some scholars in South Asia but not in Indian subcontinent.
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".