Île aux Cochons is the westernmost island of the archipelago, lying some 30 km north-west of Île des Pingouins and 15 km south-west of the Îlots des Apôtres.

It is an eroded volcanic dome, scattered with inactive craters, and a coastline consisting partly of low cliffs.

[1] The island has been identified as an Important Bird Area (IBA) by BirdLife International as a breeding site for seabirds, and notably for its large penguin populations.

[1] In a 2018 report in Antarctic Science, researchers estimated that the population of King penguins on the island had dwindled from 500,000 breeding pairs to just 60,000.

[2] Researchers are still uncertain of the cause but have suggested climate change, disease, or resource scarcity.