Lake Hillier is a saline lake on the edge of Middle Island, the largest of the islands and islets that make up the Recherche Archipelago in the Goldfields-Esperance region, off the south coast of Western Australia. It is particularly notable for its pink colour. A long and thin shore divides the Southern Ocean from the lake.
Lake Hillier is about 600 metres (2,000 ft) in length by about 250 metres (820 ft) in width. The lake is surrounded by a rim of sand and a dense woodland of paperbark and eucalyptus trees with a narrow strip of sand dunes covered by vegetation separating its northern edge from the northern coast of Middle Island. The most notable feature of the lake is its pink colour. The vibrant colour is permanent, and does not alter when the water is taken in a container. The source of the pink colour is considered to be due to the presence of the organism Dunaliella salina. Air is the best mode of transportation for viewing the lake.
Lake Hillier was visited by the Matthew Flinders' expedition on 15 January 1802. Flinders' journal entries are considered to be the first written records of the lake. Flinders observed the pink lake after ascending the island's highest peak (now called Flinders Peak).
The lake was subject to salt mining during the late 19th century. The salt mining enterprise is reported as failing for a number of reasons including “the toxicity of the salt collected for consumption”.
As of 2012, the lake is part of the protected area known as the Recherche Archipelago Nature Reserve and is the feature of a recreational walking trail which circumnavigates its shoreline.
Despite the high salt content levels (comparable to those of the Dead Sea), Lake Hillier is safe to swim in. However, there are very few ways to reach Lake Hillier. Helicopter is one of the most common methods of travel. Cruises are also an option for passengers wanting to visit the isolated lake, and surrounding forest area.
As recently as 2012, Lake Hillier has been located within the boundaries of the Recherche Archipelago Nature Reserve. Since 2002, the lake itself has been considered to be a wetland of “subregional significance”.
