Hallett Cove is one of South Australia’s foremost natural science treasures. Exposed examples for prime geological concepts of superposition of strata, depositional unconformities (representing time breaks), and folding and faulting of sedimentary rocks are clearly displayed. Professor Ralph Tate discovered evidence of ancient glaciation in the form of polished and striated rock surfaces on the clifftops (Tate 1877) and the site has attracted scientific attention ever since. The area has seen at least three separate glaciations in its long history, and displays evidence of a cold, dry, windy climate during a fourth. Recognition of past climatic variations provides a historical context for understanding current climate change. Besides its geoscientific features, Hallett Cove is an important anthropological and botanical site. Aboriginal artefacts, including hammer stones, flaked cutters and scrapers, were discovered in sandy sediments overlying calcrete at Hallett Cove by Harold Cooper, and shown to anthropologist Norman Tindale in 1934 (Cooper, Kenny and Scrymgour 1972). The steep and inaccessible slopes between the plateau and the cliffs have ensured the survival of native scrub, and the coastal dunes are vegetated with plants typical of this environment, including daisies, ruby saltbush, pigface, sedge and spinifex. Cooper, Kenny and Scrymgour (1972) described 20 plant species from Hallett Cove, illustrating them with sketches, and also outlined some of the early history of European settlement. The proximity to Adelaide, the diversity of rock types and field relationships, the evidence of past glaciations, and the remnant native flora and fauna have made Hallett Cove a highly valued conservation park with wide application in public education. Many generations of school and university students in disciplines as diverse as geography, history, geology, paleontology, botany, zoology, archaeology and environmental science have enjoyed informative excursions to this site. Despite publication of at least five field guides to Hallett Cove (Talbot and Nesbitt 1968; Cooper, Kenny and Scrymgour 1972; Giesecke, Whatmough and Major 1999; Mines and Energy South Australia 1996; Willoughby 2010) and the erection of explanatory signs at sites of geoscientific significance by the Department of Mines and Energy throughout the park in the 1980s, no modern detailed geological map using current stratigraphic nomenclature has hitherto been published. Following frequent inquiries made lately about whether such maps of Hallett Cove do exist, the author drew upon personal observations gathered over many years to construct a new geological map of the conservation park. The present ready availability of fully rectified colour aerial imagery enabled photo-interpretation of lithological boundaries, and their interpolation between control points located by global positioning system (GPS). Cartography was carried out simultaneously with photo-interpretation, on screen, using geographic information system (GIS) software. Symbols and colours for geological units were selected to approximate widely used colour schemes and lithological overprints.