North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea.
North America covers an area of about 24,709,000 square kilometers (9,540,000 square miles), about 4.8% of the planet's surface or about 16.5% of its land area. As of July 2008, its population was estimated at nearly 529 million people across 23 independent states, representing about 7.5% of the human population. North America is the third-largest continent in area, following Asia and Africa, and the fourth in population after Asia, Africa, and Europe.
The first people to live in North America were Paleoindians who began to arrive during the last glacial period by crossing the Bering land bridge. They differentiated into a number of diverse cultures and communities across the continent. The largest and most advanced Pre-Columbian civilizations in North America were the Aztecs in what is now Mexico and the Mayans in Central America. European colonists began to arrive starting in the 16th and 17th centuries, wiping out large numbers of the native populations and beginning an era of European dominance.
The Americas are usually accepted as having been named after the Italian explorer Amerigo Vespucci by the German cartographers Martin Waldseemüller and Matthias Ringmann. Vespucci, who explored South America between 1497 and 1502, was the first European to suggest that the Americas were not the East Indies, but a different landmass previously unknown by Europeans. In 1507, Waldseemüller produced a world map, in which he placed the word "America" on the continent of South America, in the middle of what is today Brazil. He explained the rationale for the name in the accompanying book Cosmographiae Introductio,
For Waldseemüller, no one should object to the naming of the land after its discoverer. He used the Latinized version of Vespucci's name (Americus Vespucius), but in its feminine form "America", following the examples of "Europa" and "Asia".