How many sub continents are there

Greenland, India, the Middle East and Europe could be described as four subcontinents : Greenland because it is bigger than an island and smaller than a continent, the Middle East and India because they are geographically separate from their larger continent (Asia). Europe, however, is only a subcontinent if considered part of Eurasia.

A subcontinent is usually defined as a peninsula or isthmus of a continent, one that has distinct properties (as on a tectonic plate). It can also include large islands off the shore of a continent.

Fifteen areas that may qualify as subcontinents:

  1. Scandinavia
  2. Iberia (Spain and Portugal)
  3. Caucasia (between the Black and Caspian Seas)
  4. Arabia
  5. the Horn of Africa
  6. India
  7. Southeast Asia
  8. East China
  9. Amuria (Korea, Manchuria, southeastern Siberia)
  10. Kolyma (eastern Siberia)
  11. Alaska
  12. Greenland
  13. Quebec-Labrador
  14. Meso-America (Mexico, Central America)
  15. Patagonia (the southern part of the cone of South America)

A good rule of thumb is that any peninsula, isthmus, or island over 500,000 square miles is a subcontinent. Europe is mostly a huge peninsula, but is usually considered a continent (non-peninsular Europe is the portion of Russia west of the Urals). Australia is a huge island, but is considered a continent.
The only subcontinent in the world is India.