Hallett Cove Conservation Park is the most geologically significant coastal destination in South Australia and one of the most scientifically remarkable accessible landscapes in the Southern Hemisphere, sitting approximately 20 kilometres south of Adelaide at the edge of the Gulf St Vincent. The park holds great cultural significance to the Kaurna people, including a significant site on the Tjilbruke Dreaming Track, and contains Aboriginal artefacts used by the Kaurna people approximately 2,000 years ago and by the older Kartan people up to 40,000 years ago. The Kaurna name for the Amphitheatre area within the park is Murrkangga, meaning crying place, a name connected to the tears of Tjilbruke, the Kaurna creator whose Dreaming trail passes along this entire stretch of Fleurieu coastline. The park and the cove itself are named after John Hallett, who arrived in South Australia on 6 November 1836 aboard the 316-tonne barque Africaine. Entering the area in 1837 while looking for missing stock, he took up land for grazing, and the area became known as Hallett's Cove.

The park holds one of Australia's most outstanding geological and archaeological sites, recording an Australian ice age some 280 million years ago and providing a record of more than 1,700 Aboriginal artefacts. One of Hallett Cove's unique claims is evidence from three ice ages found across the park, with geological evidence starting in the Precambrian era approximately 500 million years ago, visible in the cliff faces and wave-cut platforms. When development pressure threatened the area in the 1960s and 1970s, a community campaign involving thousands of letters to the government and the personal commitment of Premier Don Dunstan resulted in the land being purchased for public protection. In 1976, the park was officially named a Conservation Park to protect its extraordinary geology and history.

The beach at Hallett Cove is a small, rocky cove rather than a traditional sandy swimming beach, with the Field River running to the sea at its southern end. It faces west across the Gulf St Vincent and is sheltered in its south-western corner, where swimming and snorkelling are permitted along the beach in the south-western corner of the park. The rocky wave-cut platforms extend from the base of the Black Cliff below the conservation park and are not suitable for casual lap swimming, though the sheltered cove pocket does provide calm, clear water in summer for confident snorkellers. The beach is not the primary reason to visit: the geological formations, clifftop boardwalk, and the extraordinary views from the lookouts above are what make Hallett Cove irreplaceable. The smooth siltstone pavement at the top of Black Cliff was produced by rock flour frozen in the ice sheet polishing the rock as it moved, while the striations were caused by larger rocks dragged along the bottom of the glacier.

The Sugarloaf is an iconic geological formation in the Amphitheatre area, which was once filled by a glacial lake millions of years ago. Standing next to the Sugarloaf, you can see clearly different coloured sediment layers: the dark red layer at the base formed by sediments left behind by the glacial lake, lighter Permian wind-blown sands above that, and top soils carried by creeks and rivers from the surrounding land at the very top. The formation is extremely fragile and must not be touched or climbed. The two most remarkable views in the park are from the Black Cliff Lookout and the Amphitheatre Rim, which together offer the most complete perspective of the coastline and geological formations.

Photographically, Hallett Cove is exceptional across all seasons. Winter provides opportunities for capturing dramatic photographs of stormy seas and crashing waves, especially from Black Cliff Lookout. Spring offers sunny days and a vibrant display of wildflowers along the Glacial Hike, complementing the park's geological formations. Summer is ideal for exploring the underwater world through snorkelling, while autumn offers pleasant weather for walking the park's trails. The Sugarloaf with its layered geology against the open gulf is among the most distinctive natural photography subjects on the entire Adelaide coast. From Black Cliff Lookout, the ocean crashing against the ancient Precambrian rock platform below produces a shot of genuine drama. Sunset from the clifftops is particularly spectacular, as the cliff faces change colour in the warm light.

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