Isla Grande de Tierra del Fuego is an island near the southern tip of South America from which it is separated by the Strait of Magellan. Its western part is in Chile, while the east is in Argentina. It forms the largest part of Tierra del Fuego.

The island has an area of 47,992 km², making it the 29th largest island in the world. Its two main towns are Ushuaia and Rio Grande, both in Argentina, while its highest point is Monte Darwin , in Chile.