Nepean River

Nepean River Cowpasture River, Mittagong River, London River[1]
Nepean River, Looking north towards Penrith, 2006
Etymology	In honour of Evan Nepean, in 1789[1]
Native name	Yandhai (Dharuk)
Location
Country	Australia
State	New South Wales
Region	Sydney Basin (IBRA), Southern Highlands, Macarthur, Greater Western Sydney
District	Wingecarribee, Wollondilly, Camden, Penrith, Hawkesbury
City	Penrith
Physical characteristics
Source	Mittagong Range
• location	near Robertson
• coordinates	34°33′59″S 150°36′01″E / 34.56639°S 150.60028°E / -34.56639; 150.60028
• elevation	766 m (2,513 ft)
Mouth	confluence with the Grose River to form the Hawkesbury River
• location	near Yarramundi
• coordinates	33°36′32″S 150°41′58″E / 33.60889°S 150.69944°E / -33.60889; 150.69944
• elevation	92 m (302 ft)
Length	178 km (111 mi)
Basin features
River system	Hawkesbury-Nepean catchment
Tributaries
• left	Erskine Creek, Breakfast Creek (New South Wales), Warragamba River, Glenbrook Creek
• right	Burke River (New South Wales), Cordeaux River, Cataract River (Wollondilly)
National park	Blue Mountains National Park
[2]

The Nepean River (Darug: Yandhai^[1]), is a major perennial river, located in the south-west and west of Sydney, New South Wales, Australia. The Nepean River, and, continuing by its downstream name, the Hawkesbury River, almost encircles the metropolitan region of Sydney.

The headwaters of the Nepean River rise near Robertson, about 100 kilometres (62 mi) south of Sydney and about 15 kilometres (9.3 mi) from the Tasman Sea. The river flows north in an unpopulated water catchment area into Nepean Reservoir, which supplies potable water for Sydney. North of the dam, the river forms the western edge of Sydney, flowing past the town of Camden and the city of Penrith, south of which flowing through the Nepean Gorge. Near Wallacia it is joined by the dammed Warragamba River; and north of Penrith, near Yarramundi, at its confluence with the Grose River, the Nepean becomes the Hawkesbury River.