Nepean Dam, located approximately 100 kilometres south of Sydney, is a heritage-listed reservoir nestled near Bargo in the Southern Highlands. Completed in 1935, it was the final addition to the Upper Nepean Scheme, a series of four dams designed to secure Sydney’s water supply. The dam wall stands 81 metres high, creating a 325-hectare lake with a capacity of over 70,000 megalitres, fed by a 320 square kilometre catchment area .​
Constructed during the interwar period, the dam showcases Art Deco architectural elements and was built using materials transported via a dedicated railway line from the Main Southern Line near Bargo . Today, Nepean Dam supplies water to the Macarthur and Illawarra regions, Wollondilly Shire, and metropolitan Sydney .
Visitors can enjoy scenic views of the dam wall and lake, with picnic areas and walking paths available in the surrounding bushland. The dam is accessible via Avon Dam Road, Bargo, and is open to the public on weekends, offering a tranquil setting for relaxation and exploration