North America is a continent located completely within the Northern Hemisphere and is mostly located within the Western Hemisphere. 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 sq km (9,540,000 sq mi), 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 seven sovereign states. North America is the third-largest continent in area, following Asia and Africa, and the fourth in population after Asia, Africa, and Europe.