Dirk Hartog Island is an island off the Gascoyne coast of Western Australia, within the Shark Bay World Heritage Area. It is about 80 kilometres long and between 3 and 15 kilometres wide and is Western Australia's largest and most western island. It covers an area of 620 square kilometres and is approximately 850 km north of Perth. It was named after Dirk Hartog, a Dutch sea captain, who first encountered the Western Australian coastline close to the 26th parallel south latitude, which runs through the island. After leaving the island, Hartog continued his voyage north-west along the mainland coast.