The 629-hectare (1,550-acre) national park is situated approximately 70 kilometres (43 mi) southwest of the Sydney central business district, and just to the west of Thirlmere.

[1] Two of the lakes have dried out since the mid 1980s due to removal of groundwater in the region secondary to coal mining at the Tahmoor Colliery.

[5] The main feature of the park are the lakes, thought to have formed around 15 million years ago by geological activity, the land lifting and largely cutting them off from the local river system.

[6] The habitat around the lakes is open sclerophyll forest, the dominant trees being rough-barked apple (Angophora floribunda) nearby and sydney peppermint (Eucalyptus piperita) and red bloodwood (Corymbia gummifera) on elevated areas.

The understory species include many familiar sydney sandstone flora such as members of the genera Banksia, Acacia, pea flowers, and the New South Wales waratah (Telopea speciosissima)[2]