Nepean River in the context of "Mooney Mooney Creek"

The Blue Mountains (Gundungurra/Dharug: Colomatta or Gulumada) are a mountainous region and a mountain range located in New South Wales, Australia. The region is considered to be part of the western outskirts of the Greater Sydney area. The region borders on Sydney's main metropolitan area, its foothills starting about 50 kilometres (31 mi) west of centre of the state capital, close to Penrith. The public's understanding of the extent of the Blue Mountains is varied, as it forms only part of an extensive mountainous area associated with the Great Dividing Range. As defined in 1970, the Blue Mountains region is bounded by the Nepean and Hawkesbury rivers in the east, the Coxs River and Lake Burragorang to the west and south, and the Wolgan and Colo rivers to the north. Geologically, it is situated in the central parts of the Sydney Basin.

The Blue Mountains Range comprises a range of mountains, plateau escarpments extending off the Great Dividing Range about 4.8 kilometres (3.0 mi) northwest of Wolgan Gap in a generally southeasterly direction for about 96 kilometres (60 mi), terminating at Emu Plains. For about two-thirds of its length it is traversed by the Great Western Highway, the Main Western railway line and the proposed Blue Mountains tunnel. Several established towns are situated on its heights, including Katoomba, Blackheath, Mount Victoria, and Springwood. The range forms the watershed between Coxs River to the south and the Grose and Wolgan rivers to the north. The range contains the Explorer Range and the Bell Range.

The Hawkesbury River, or Hawkesbury-Nepean River (Dharug: Dyarubbin) is a river located northwest of Sydney, New South Wales, Australia. The Hawkesbury River and its associated main tributary, the Nepean River, almost encircle the metropolitan region of Sydney. The river between Wisemans Ferry and the Pacific Ocean marks the boundary of Greater Metropolitan Sydney in the south and the Central Coast region to the north.

The Hawkesbury River has its origin at the confluence of the Nepean River and the Grose River, to the north of Penrith and travels for approximately 120 kilometres (75 mi) in a north–easterly and then a south–easterly direction to its mouth at Broken Bay, about 15 kilometres (9.3 mi) from the Tasman Sea. The Hawkesbury River is the main tributary of Broken Bay. Secondary tributaries include Brisbane Water and Pittwater, which, together with the Hawkesbury River, flow into Broken Bay and thence into the Tasman Sea north of Barrenjoey Head.

Penrith is a city in New South Wales, Australia, located in Greater Western Sydney, 55 kilometres (31 mi) west of the Sydney central business district on the banks of the Nepean River, on the outskirts of the Cumberland Plain. Its elevation is 32 metres (105 ft).

Penrith is the administrative centre of the local government area of the City of Penrith.

The Coxs River, a perennial river that is part of the Hawkesbury-Nepean catchment, is located in the Central Tablelands, Blue Mountains, and Macarthur regions of New South Wales, Australia.

Lake Burragorang is a man-made reservoir in the lower Blue Mountains of New South Wales, Australia, serving as a major water supply for greater metropolitan Sydney. The dam impounding the lake, the Warragamba Dam, is located approximately 60 kilometres (37 mi) southwest of the Sydney central business district.

Lake Burragorang is within the World Heritage Site of the Greater Blue Mountains Area. The 2,031-gigalitre (4.47×10 imp gal; 5.37×10 US gal) reservoir collects water from the converged flows of the Coxs, Kowmung, Nattai, Wingecarribee, Wollondilly, and Warragamba rivers and their associated tributaries, all within the Nepean and Hawkesbury River catchment.

The Wolgan River, a watercourse of the Hawkesbury-Nepean catchment, is located in the Central Tablelands region of New South Wales, Australia.

The Colo River, a perennial stream that is part of the Hawkesbury-Nepean catchment, is located in the Central Tablelands of New South Wales, Australia.

Emu Plains is a suburb of Sydney in the state of New South Wales, Australia. It is 58 kilometres (36 mi) west of the Sydney central business district, in the local government area of the City of Penrith and is part of the Greater Western Sydney region.

Emu Plains is on the western side of the Nepean River, located at the foot of the Blue Mountains.