The Stirling Range or Koikyennuruff is a range of mountains and hills approx 98 km from Albany. It is over 60 km wide from west to east, stretching from the highway between Mount Barker and Cranbrook eastward past Gnowangerup. The Stirling Range is protected by the Stirling Range National Park, which was gazetted in 1913, and has an area of 1,159 km2.
The range is one of the richest areas for flora in the world. The low-nutrient soils support five major vegetation communities: shrubland and mallee-heathland at higher altitudes; and woodland, wetland and salt lake communities on lower slopes and plains. Ninety families, 384 genera, and over 1500 plant species occur there, 87 of which are found nowhere else. This represents more than a third of the known flora of the southwest, and includes more species of wildflowers than in the entire British Isles.
The range has been identified by BirdLife International as an Important Bird Area (IBA) because it supports populations of endangered short-billed black cockatoos and western whipbirds, and is visited by endangered long-billed black-cockatoos. Significant biome-restricted or range-restricted bird species found in the range include red-capped and regent parrots, western rosellas, rufous treecreepers, red-winged and blue-breasted fairywrens, purple-gaped honeyeaters, western spinebills, western thornbills, western yellow and white-breasted robins, and red-eared firetails.
The plains in the Stirling Range region were the hunting grounds for small groups of Indigenous Australians before European settlement. At least two tribes frequented the area: the Qaaniyanpeople in the west, and the Koreng people in the east. The Stirling Range played an important role in their culture, appearing in a number of Dreamtime stories.
The first recorded sighting of the Stirling Ranges by a European explorer was by Matthew Flinders on 5 January 1802. While sailing along the south coast of Australia, just east of King George Sound, he noted at a distance of eight leagues (44 km) inland a chain of rugged mountains, the easternmost of which he named Mount Rugged (now called Bluff Knoll).
Notable features include Toolbrunup, Bluff Knoll (the tallest peak for a thousand kilometres or more in any direction and most popular tourist attraction), and a silhouette called The Sleeping Princess which is visible from the Porongurup Range. Popular recreational activities include bushwalking, abseiling and gliding.