Asia is the largest continent, it is 17,085,000 square miles (44,283,362 square kilometres). This means it comprises of 29.9% of the land on Earth. Asia is home to approximately 3 billion people throughout approximately 50 countries.

The countries of Asia (alphabetical order)

Sources:
www.geography.com
Compton's Interactive Encyclopedia
Gritchka

/msg me with corrections/additions. I can't be sure I got all the countries.