South Australia · Attraction
Cave Garden / Thugi
City sinkhole, ancient heart
schedule 1 min read / Updated Jun 2026
Right in the centre of Mount Gambier, this sunken limestone garden surrounds a sinkhole that has shaped the city since its founding. Known to the Bungandidj people as Thugi, meaning bullfrogs, the cave once supplied the town's first fresh water. Visitors can stroll landscaped gardens at street level or descend steps to a viewing platform inside the 30-metre-deep cavity.
The sinkhole formed when an underground cave beneath volcanic rock and ash collapsed, exposing groundwater below. The Bungandidj people knew this place long before European arrival, and the name Thugi was formally added to the site's dual title by the City of Mount Gambier in 2022.
European settlers found the cave during the 1845-46 survey, and it remained the town's primary water source through the 1850s. The first post office, town hall and a hotel were all built around the reserve, giving Cave Garden / Thugi a central place in the city's colonial history.
Today the gardens are shaded and well-maintained, with a stepped descent into the cave itself. After heavy rainfall, a small waterfall sometimes runs down the limestone walls. Entry is free and the space is open around the clock, making it an easy addition to any Mount Gambier itinerary.
Scenic views
Lookouts near Cave Garden / Thugi.
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