Umpherston Sinkhole

Umpherston Sinkhole, also known as the Sunken Garden, is a limestone sinkhole garden in Mount Gambier, South Australia. Formed by the collapse of a cave roof, it was transformed into a terraced garden by James Umpherston in 1886. Located on Jubilee Highway East, the site features lush plantings, hydrangeas, hanging vines and floodlit night displays. It is a free, publicly accessible attraction managed by the City of Mount Gambier and a key Limestone Coast visitor site.

Visitors can expect a large collapsed limestone sinkhole converted into a terraced sunken garden. From an upper viewing platform, stairs lead down into the sheltered garden floor surrounded by vertical limestone walls draped with vines and ferns. The garden contains lawns, hydrangeas, palms and other plantings, with paved paths, terraces and seating. The sinkhole is floodlit after dark and can be viewed from above at night. The surrounding reserve includes lawns, picnic areas and parking.