South Asia is often considered synonymous with the term Indian subcontinent, and includes the following neighboring states:

India, Pakistan and Bangladesh; constituting the bulk of the Indian subcontinent the Himalayan States: Nepal and Bhutan the Indian Ocean Island States: Sri Lanka, the Maldives and India's Andaman, Nicobar and Lakshadweep islands.

All of these countries are members of the South Asian Association for Regional Cooperation (SAARC).

Geographically, the Indian subcontinent would additionally include some disputed territory currently controlled by China and Myanmar. It covers about 4,480,000 km² (1,729,738 mi²), or 10 percent of the Asian continent. However, its population accounts for about 40 percent of Asia. Some or all of Afghanistan is sometimes considered part of the region of South Asia because Afghanistan has shared many historical currents with the region, but is not located on the subcontinent.

The term "South Asia"' is a common contemporary term for what in times before 1947, the end of the British Raj and the beginning of the First Indo-Pakistani War, was simply known as "British India", Hindustan, or references were used to denote local empires such as the Mughal Empire, Delhi Sultanate, etc. as the borders of present South Asia were largely defined by British rule. Prior to Independence that term referred to those portions of the country that were directly administered by the British, as opposed to the princely states.

Historically, South Asia and South-East Asia together constitute what is known as the East Indies, with the first being defined as Hither India or India Citerior and Further India or India Ulterior. These terms, however, have ceased to be current and have become arcane and largely used, if at all, by academics, with only the "East Indies" still retaining some current usage.

Politically, South Asia makes sense as it does not apply only to countries found on the Indian plate, geologically, but can include other countries due to geographic proximity. The United Nations, for example includes Iran, Afghanistan, and Myanmar in South Asia for its own geographic reasons, while others exclude these countries. Myanmar (Burma), is often grouped in this region due to the fact that it was associated with the British colony of India, during colonial times.