Elephant Island is an ice-covered, mountainous island off the coast of Antarctica in the outer reaches of the South Shetland Islands, in the Southern Ocean. The island is situated 245 kilometres (152 miles) north-northeast of the tip of the Antarctic Peninsula, 1,253 kilometres (779 miles) west-southwest of South Georgia, 935 kilometres (581 miles) south of the Falkland Islands, and 885 kilometres (550 miles) southeast of Cape Horn. It is within the Antarctic claims of Argentina, Chile, and the United Kingdom.

The Brazilian Antarctic Program maintains a shelter on the island, Goeldi, and formerly had another (Wiltgen) supporting the work of up to six researchers each during the summer. Wiltgen was dismantled in the summers of 1997 and 1998.

Elephant Island's name is attributed to both its elephant head-like appearance and the sighting of elephant seals by Captain George Powell in 1821, one of the earliest sightings. In Russia, it is still known by the name given by its discoverers in 1821 – Mordvinov Island.

Elephant Island marks the western end of the South Scotia Ridge. The island is oriented approximately east–west, with a maximum elevation of 973 m (3,192 ft) at Mount Pendragon. The weather is normally foggy with much snow, and winds can reach 160 km/h (100 mph). Significant named features are Cape Yelcho, Cape Valentine, and Cape Lookout at the northeastern and southern extremes, and Point Wild, a spit on the north coast. The Endurance Glacier is the main discharge glacier.

Elephant Island is part of the Scotia metamorphic complex, which was created by Cretaceous sea floor sediments being scraped off and metamorphosed at the Scotia subduction zone. The resulting rocks are phyllites, blueschists, and greenschists typical of an accretionary wedge, with increased metamorphism from northeast to southwest. These rocks are at the surface here because of uplift along the Shackleton Fault Zone where it meets the South Scotia Ridge.

The barren island supports no native terrestrial flora or fauna, although seasonal colonies of chinstrap, gentoo, and macaroni penguins congregate in their thousands to mate and breed during warmer periods. Other seabirds found on the island include the Antarctic shag and tern, brown skua, Cape petrel, giant petrel, kelp gull, snowy sheathbill, and Wilson's storm-petrel. Antarctic fur seals, leopard seals, and southern elephant seals are also found around the island seasonally.

The island is historically significant as the desolate refuge of the British explorer Ernest Shackleton and his crew in 1916 following the loss of their ship Endurance in the Weddell Sea. Shackleton's remarkable journey and the survival of his crew against all odds on Elephant Island is a tale of endurance and determination that continues to inspire adventurers and history enthusiasts worldwide.

The Endurance Memorial Site at Point Wild on Elephant Island pays tribute to this incredible story of survival. Visitors to the island can witness the harsh conditions faced by Shackleton and his crew, surrounded by the stunning Antarctic landscape. Elephant Island stands as a testament to human resilience and the unwavering spirit of exploration in the face of adversity.