Blue lakes, ancient caves: Your guide to Mount Gambier's State Heritage Areas

A State Heritage Area is a clearly defined region with outstanding natural or cultural elements significant to South Australia's development and identity.

Mount Gambier is 435km from Adelaide, or just under a five-hour drive. In the Limestone Coast region, Mount Gambier is known for its unique and striking volcanic landscape.

Here are four fascinating sites you can visit there.

1. Mount Gambier Thugi / Cave Garden

The Thugi / Cave Garden is located within the Mount Gambier city centre. It’s a shady, landscaped park surrounding a limestone sinkhole, with steps leading down into the 'cave' to a viewing platform. It’s a large, beautiful sinkhole about 25 metres wide and 18 metres deep. A waterfall commonly occurs in the sinkhole during wet weather. Every evening in the Thugi / Cave Garden, historic local photos and pictures are projected onto the back of buildings for viewing within the garden.

What is the history of Thugi / Cave Garden?

It likely formed when an underground cave beneath volcanic rock and ash (around 5,000 years old) collapsed, revealing a pool of groundwater. This type of natural geological feature is called a cenote.

Mount Gambier was settled around the abundant fresh water supply from the sinkhole, influencing the overall development and planning of the city. As Mount Gambier developed, the area around the sinkhole became home to key public buildings, forming the town’s civic centre. Today, the landscaped park around the sinkhole includes the ornate marble Gardiner Fountain.

The State Heritage Area also has several large, impressive buildings, mostly two storeys high, built in a grand style and positioned right on or very close to the street. Five of these historic commercial or civic buildings are State heritage-listed:

• Mount Gambier Post Office – formerly Telegraph office (1865). Today, the building is not used as a Post Office.
• Riddoch Arts and Cultural Centre – formerly the Institute (1868) and King's Theatre (1907). Check out the free daily screening of ‘Volcano’, a movie that tells the powerful story of how Mount Gambier and the Kanawinka region were formed. It begins with the local Aboriginal Dreamtime story of Craitbul and his giant ovens, then takes you on an awe-inspiring journey through the eight major volcanic eruptions that shaped the land.
• Mount Gambier Town Hall / City Hall (1882).
• Jen’s Hotel (1884).
• Rubenkonig building – formerly Jen’s Hotel Annexe (1902).

Other significant buildings surrounding Thugi / Cave Garden include the Mount Gambier Library and the Sir Robert Helpmann Theatre (named after the world-renowned Australian actor, dancer, choreographer and director).

What does ‘thugi’ mean?

‘Thugi’, meaning ‘bullfrogs’ in Bunganditj, the reclaimed language of the Boandik People, was added to the name of the Cave Garden in 2022.

2. Mount Gambier Volcanic Complex

The Mount Gambier Volcanic Complex is the most recent place in Australia where a volcano was active.

It’s been a popular tourist spot since the 1880s and includes several craters and other volcanic features on the southern edge of the city.

What is the history of the Volcanic Complex?

About 4,000 years ago, volcanic activity in the area heated the shallow groundwater, causing steam to build up and trigger explosions.

These explosions formed craters (called maars) and steam vents. The craters filled with groundwater, creating the four lakes that are now popular tourist attractions. Today, you can admire the stunning water in the Blue Lake / Warwar and the Valley Lake / Ketla Malpi. The Leg of Mutton Lake / Yatton Loo and Browne Lake / Kroweratwari are no longer lakes containing water but are still great to visit.

This group of crater lakes is an important site for studying volcanoes in Australia, and Mount Gambier is recognised as a South Australian Geological Monument.

3. Mount Gambier Blue Lake

Warwar / the Blue Lake is famous for its striking colour change – from grey in winter to bright blue in summer.

It’s the largest crater in the Mount Gambier Volcanic Complex and is now a permanent freshwater lake that supplies water to the local area.

When is the best time to see the Blue Lake?

The best time to view the Blue Lake is between November and March. The lake’s colour change happens because of natural interactions between organic material and minerals in the water.

How long is the walk around the Blue Lake?

The road and walking track around the circumference of the Blue Lake is 3.6 kilometres and includes access to many lookouts.

Monuments around the lake mark important local people and events, and the Blue Lake is considered one of the world’s best-preserved examples of this type of volcanic crater.

Guided tours of the Blue Lake Pumping Station offer a novel tourist experience.

What does ‘Warwar’ mean?

‘Warwar’, meaning ‘the sound of many crows’ or ‘crow country’ in Bunganditj, the reclaimed language of the Boandik People.

4. Mount Schank

The volcanic cinder cone of Mount Schank is a striking landscape feature around 12 kilometres south of Mount Gambier. Mount Schank's cone-shaped landform is a rare South Australian example of volcanic activity in recent geological time.

What is the history of Mount Schank?

Mount Schank erupted around 4,300 to 5,000 years ago after a fault in the limestone triggered volcanic activity. This created lava flows, ash deposits, and a large, dry crater about 500 metres wide.

The eruptions were smaller than those at Mount Gambier but still shaped the surrounding landscape. Scientific studies show Mount Schank is slightly older than Mount Gambier.

Unlike Mount Gambier, Mount Schank is outside urban areas. Despite farming and quarrying, its cone shape remains intact. It is recognised as a South Australian Geological Monument.

New Heritage Standards for Mount Schank and Mount Gambier areas

Heritage South Australia are seeking community feedback on draft Heritage Standards to ensure future development respects the heritage values of the areas. The three State Heritage Areas are:

• Mount Schank
• Mount Gambier Thugi / Cave Garden and Civic Centre
• Mount Gambier Volcanic Complex.

Once approved, the final Heritage Standards will be used to guide development decisions in the State Heritage Areas. Your feedback will help inform the final Heritage Standards. The drafts are currently open for public feedback on the YourSAy platform, and community consultation sessions. Visit the YourSAy page for more information and to complete the brief survey. Consultation closes on 15 August 2025.

Can you do cave diving in Mount Gambier?

Yes you can do cave diving at Hells Hole, which is located in Caveton, south of Mount Gambier. There is restricted access into the sinkhole. Visitors must be a current member of the Cave Divers Association of Australia to gain diving access and a permit must be obtained from Forestry SA.

More information

Read more about State Heritage Areas and the work the Department for Environment and Water are doing to protect them.

Check out Mount Gambier’s beautiful Umpherston Sinkhole on the South Australian Tourism Commission website.

Want more information on visiting Mount Gambier? View the Visit Mount Gambier website.

Looking for National Parks or Conservation Parks located near Mount Gambier? Here is a list of 7 parks close by:

• Telford Scrub Conservation Park
• Tantanoola Caves Conservation Park
• Penambol Conservation Park
• Ewens Ponds Conservation Park
• Dingley Dell Conservation Park
• Douglas Point Conservation Park
• Piccaninnie Ponds Conservation Park

Main image: Mount Gambier Blue Lake / Warwar. Credit: South Australian Tourism Commission / Adam Bruzzone.