Asia is the world's largest and most populous continent , located primarily in the Eastern and Northern Hemisphere. It covers 6.7% of the land surface and 30% of the land area. Asia is home to an estimated 4.3 billion people, more than 80% of the world's population. Like most of the world , Asia has a high growth rate in modern times. During the twentieth century , for example , Asia's population has almost quadrupled, much like the world's population . Asia and Europe are separated by the Ural Mountains , the Ural River , the Caspian Sea , the Black Sea, and the Mediterranean. In addition, the Red Sea and the Suez Canal have separated Asia from Africa, and the northeastern Bering Strait has separated it from North America. Note that the Bering Strait is located on one side of Russia's Ulena in Asia and on the other side Alaska in North America. The narrowest part of the system is only 72 km wide , which means that the distance from this part of the Bering system to the North American continent is only 72 km.