South Asia is the southern subregion of Asia, which is defined in both geographical and ethnic-cultural terms. As commonly conceptualised, South Asia consists of the countries predominantly Afghanistan Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka,
Topographically, it is dominated by the Indian subcontinent and defined largely by the Indian Ocean in the south, and the Himalayas, Karakoram, and Pamir mountains in the north. The Amu Darya, which rises north of the Hindu Kush, forms a part of the northwestern border. On land (clockwise), South Asia is bounded by Central Asia to the north, East Asia and Southeast Asia to east, and West Asia to the west.
The South Asian Association for Regional Cooperation (SAARC) is an economic cooperation organization in the region which was established in 1985 and includes all eight nations comprising South Asia. The core countries of South Asia have a total area of , which is 10% of the Asian continent. The population of the region, under the broader definition, is about 1.9 billion or about one-fourth of the world's population, making it both the most populous and the most densely populated geographical region in the world.
In 2022, South Asia had the world's largest populations of Hindus, Muslims, Sikhs, Jains, and Zoroastrians. South Asia alone accounts for 90.47% of Hindus, 95.5% of Sikhs, and 31% of Muslims worldwide, as well as 35 million Christians and 25 million Buddhists.
The geographical extent is not clear cut as systemic and foreign policy orientations of its constituents are quite asymmetrical. Beyond the core territories of the Indian Empire (territories of the British Empire which were under the system of British Raj), there is a high degree of variation as to which other countries are included in South Asia. There is no clear boundary – geographical, geopolitical, socio-cultural, economical, or historical – between South Asia and other parts of Asia, especially Southeast Asia and West Asia.