South America is a continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with about a quarter in the Northern Hemisphere. It is bordered on the west by the Pacific Ocean and on the north and east by the Atlantic Ocean. North America and the Caribbean Sea lie to the northwest.

South America was named in 1507 by cartographers Martin Waldseemüller and Matthias Ringmann after Amerigo Vespucci, who was the first European to suggest that the Americas were not the East Indies, but a New World unknown to Europeans.

South America has an area of 17,780,000 square kilometers (6,890,000 sq mi), or almost 3.5% of the Earth's surface. As of 2005, its population was estimated at more than 371,090,000. South America ranks fourth in area (after Asia, Africa, and North America) and fifth in population (after Asia, Africa, Europe, and North America).

South America is thought to have been first inhabited by people crossing the Bering Land Bridge, which is now the Bering Strait. Some archaeological finds do not fit this theory, and have led to an alternative theory Pre-Siberian American Aborigines. The first evidence for the existence of agricultural practices in South America date back to circa 6500 BCE, when potatoes, chillies and beans began to be cultivated for food in the highlands of the Amazon Basin. Pottery evidence further suggests that manioc, which remains a staple foodstuff today, was being cultivated as early as 2000 BCE.

By 2000 BCE many agrarian village communities had been settled throughout the Andes and the surrounding religious regions. Fishing became a widespread practice along the coast which helped to establish fish as a primary source of food. Irrigation systems were also developed at this time, which aided in the rise of an agrarian society.

South Americans cultures began domesticating llamas, vicuñas, guanacos, and alpacas in the highlands of the Andes circa 3500 BCE. Besides their use as sources of meat, and wool, these animals were used for transportation of goods (maximum load for a llama is typically 40 kg).

The continent became a battlefield of the Cold War in the late 20th century. Some governments of Argentina, Brazil, Chile, and Uruguay were overthrown or displaced by U.S.-aligned military dictatorships in the 1960s and 1970s. To curtail opposition, their governments detained tens of thousands of political prisoners, many of whom were tortured and/or killed (on inter-state collaboration, see Operation Condor). Economically, they began a transition to neoliberal economic policies. They placed their own actions within the U.S. Cold War doctrine of "National Security" against internal subversion. Throughout the 1980s and 1990s, Peru suffered from an internal conflict (see Túpac Amaru Revolutionary Movement and Shining Path). Colombia currently faces an internal conflict, often described as a civil war, which started in 1964 with the creation of Marxist guerrillas (FARC-EP) and now involves several illegal armed groups of both leftist and rightist leanings as well as the private armies of powerful drug lords and the Colombian state itself. Revolutionary movements and right-wing military dictatorships became common after World War II, but since the 1980s a wave of democratization came through the continent, and democratic rule is widespread now.

Nonetheless, allegations of corruption are still very common and several countries have developed crises which have forced the resignation of their governments, although, in most occasions, regular civilian succession has continued this far.

International indebtedness turned out into a severe problem in late 1980's, and some countries, despite having strong democracies, have not yet developed political institutions capable of handling such crises without recurring to unorthodox economical policies, as most recently illustrated by Argentina's default in the early 21st century.

During the first decade of the 21st century, South American governments have drifted to the political left, with socialist leaders being elected in Chile, Bolivia, Brazil, Venezuela and leftist presidents in Argentina, Ecuador, Peru, and Uruguay. Despite this tendency of moving to the nominal left of the political spectrum, most of South America's governments, in real terms, embrace free-market capitalism.