The 2,679-hectare (6,620-acre) national park is situated approximately 35 kilometres (22 mi) southwest of the Sydney central business district, west of the Illawarra railway line, the Princes Highway and Motorway, and the suburbs of Heathcote and Waterfall.

It is bounded by Holsworthy and Pleasure Point to the north, Heathcote and Lucas Heights to the east, the Greater Western Sydney region to the west (which include the suburbs of Glenfield, Macquarie Fields and Campbelltown), and Helensburgh to the south in the Illawarra.

In addition, a number of Europeans lived in rough huts in the park during the Great Depression, leaving behind meagre ruins at places like Myuna Creek.

Heathcote Creek cascades down a number of rock pools and small waterfalls to the Woronora River at the northern end of the park.

The ridges and drier slopes are covered in forest dominated by angophoras and eucalypts such as bloodwood, greygum, Sydney peppermint, and scribbly gum.