Thirlmere Lakes

Thirlmere Lakes National Park is a unique freshwater lake park on the Southern Highlands of New South Wales, located near Thirlmere between Camden and Wollondilly. Covering approximately 640 hectares, the park protects a chain of five freshwater lakes — Lake Thirlmere, Lake Couridjah, Lake Nerrigorang, Lake Baraba, and Lake Gandangarra — that are remarkable as the only perched freshwater lakes on the Hawkesbury Sandstone in New South Wales. These lakes are internationally significant as they are not connected to any river system and are entirely rain-fed, creating unique freshwater ecosystems.

Thirlmere Lakes National Park supports diverse freshwater and woodland wildlife. The lakes attract diverse waterbirds including ducks, grebes, and cormorants. The eastern water dragon is common along lake margins. Platypus may occur in connected drainage. Eastern grey kangaroos and common wallaroos use the woodland around the lakes. The woodland supports diverse birds including parrots and cockatoos.

The lake margins support aquatic and swamp communities including waterlilies, rushes, and sedges. Paperbark woodland fringes the shores. Scribbly gum and banksia heath covers the surrounding sandstone ridges. The interface between the freshwater lakes and the dry sandstone heath creates a distinctive ecological mosaic.

The Thirlmere Lakes are perched lakes formed in depressions in the Hawkesbury Sandstone, with clay-rich layers preventing drainage. The lakes have no surface inlets or outlets and are entirely dependent on rainfall. They represent a unique hydrological system on the typically free-draining sandstone plateau.

Warm temperate to cool temperate climate. Annual rainfall approximately 900 millimetres. Cool winters, warm summers. The lakes respond directly to rainfall patterns.

The Dharawal people are the traditional custodians of the Southern Highlands. The lakes provided freshwater resources. European settlement of the surrounding area began in the 1820s.

Thirlmere Lakes National Park was established to protect the unique perched lake system and associated freshwater ecosystems.

Lake walking tracks provide access to the five lakes. Birdwatching and photography at the lake margins. The unique ecological setting of freshwater lakes on the sandstone plateau is the primary attraction.

Picnic area and walking tracks. Access from Thirlmere via the Northern Road. Picton provides visitor services. Approximately 90 kilometres south-west of Sydney. A national parks pass applies.

Maintaining water quality in the unique lake system is critical. The lakes are highly sensitive to nutrient inputs and changes in catchment conditions. Managing visitor impact on the lake margins protects the aquatic ecosystems. Water level monitoring tracks the health of the perched lake system.