Isla Grande de Tierra del Fuego also formerly Isla de Xátiva is an island near the southern tip of South America from which it is separated by the Strait of Magellan. The western portion (61.4%) of the island is in Chile, while the eastern portion is in Argentina. It forms the major landmass in an extended group of islands or archipelago also known as Tierra del Fuego.

The Strait of Magellan, also called the Straits of Magellan, is a navigable sea route in southern Chile separating mainland South America to the north and Tierra del Fuego to the south. The strait is considered the most important natural passage between the Atlantic and Pacific oceans. The strait is approximately 570 km long and 2 km wide at its narrowest point. In 1520, the Spanish expedition of the Portuguese navigator Ferdinand Magellan, after whom the strait is named, became the first Europeans to discover it.