Riesco Island (Spanish: Isla Riesco) lies at west of the Brunswick Peninsula, Chile. It is one of the largest islands in Chile, with an area of 5,110 square kilometres (1,970 sq mi). Its highest point is at 1,830 metres (6,000 ft). The island is bordered by two large piedmont embayments: Otway Sound and Skyring Sound. The narrow Fitzroy Channel connects both bodies of water and separates the island from mainland Patagonia. The island is separated from the southern part of the Muñoz Gamero Peninsula by another narrow channel, the .