|An intermediate tide dominated drowned valley estuary|
|Name origin: In honour of King George III|
|State||New South Wales|
|Region||Greater Metropolitan Sydney|
|- left||Bunbury Curran Creek, Cabramatta Creek, Prospect Creek, Salt Pan Creek, Boggywell Creek|
|- right||Brennan's Creek, O'Hares Creek, Punchbowl Creek, Williams Creek (New South Wales), Deadmans Creek, Mill Creek (New South Wales), Woronora River|
|Source||Dharawal Nature Reserve|
|- location||south–east of Appin, Macarthur region|
|- elevation||350 m (1,148 ft)|
|- location||Taren Point|
|Length||96 km (60 mi)|
|Depth||10.5 m (34 ft)|
|Volume||271,393.5 m3 (9,584,171 cu ft)|
|Basin||930.9 km2 (359 sq mi)|
|Area||26.6 km2 (10 sq mi)|
|Website: NSW Environment and Heritage webpage|
The source of the Georges River is from the land surrounding the Dharawal Nature Reserve, approximately 80 kilometres (50 mi) to the south-west of Sydney central business district near the town of Appin and travels for approximately 96 kilometres (60 mi) in a north and then easterly direction to its mouth at Botany Bay, about 5 kilometres (3.1 mi) from the Tasman Sea. The Georges River is the main tributary of Botany Bay; with the Cooks River being a secondary tributary.
The total catchment area of the river is approximately 930.9 square kilometres (359.4 sq mi) and the area surrounding the river is managed by a large number of local government authorities and NSW Government agencies.
From its source south–west of Appin within heath habitat of Wollondilly Shire, the Georges River flows north through rugged sandstone gorges to the east of Campbelltown, roughly parallel to the Main South railway line, with its eastern bank forming a boundary with Holsworthy Army Base. At Glenfield it reaches the urban environment and then travels to Liverpool where the river turns east and flows past the suburbs of East Hills, Lugarno, and Blakehurst, before emptying into Botany Bay at Taren Point in the southern suburbs of Sydney, where it joins with the estuarine catchment.
Major tributaries include O'Hares Creek, Bunbury Curran Creek, Cabramatta Creek, Prospect Creek, Salt Pan Creek and the Woronora River. The Georges River is popular for recreational activities such as water skiing and swimming. The banks of the river along the lower reaches are marked by large inlets and indentations overlooked by steep sandstone ridges and scarps, many being home to expensive residential properties.
The Georges River features some artificial lakes in the suburb of Chipping Norton, near Liverpool. These lakes, known as the Chipping Norton Lakes, are the result of sand mining and quarrying operations in the twentieth century. The Lakes are now a popular watersports and recreational facility for the residents of the south-western suburbs of Sydney.
Liverpool Weir now forms the uppermost tidal limit and presence of salt water on the Georges River.
Georges River National Park adjoins the upper reaches of the Georges River. This bushland is some of the most pristine in western Sydney. From Appin to Glenfield, a large corridor has been protected as part of the Georges River Regional Open Space Corridor. National Park reserves allow for access to pristine areas located at Simmo's Beach, Ingleburn Reserve, Keith Longhurst Reserve, and Frere's Crossing.
Prior to the arrival of Europeans, Georges River was formerly known as Tucoerah River by the traditional custodians of the area.
In February 2007, Liverpool and Campbelltown City Council were awarded a $2 million grant from the NSW Environmental Trust under their Urban Sustainability Initiative. The grant was to allow the councils, in conjunction with Wollondilly Shire Council and the Georges River Combined Councils Committee, to develop a Comprehensive Strategic Plan focused on the rehabilitation of the catchment area.
Bridges over the Georges River include from east to west:
- Captain Cook Bridge (connecting Sans Souci to Taren Point), for cars, pedestrians and cyclists.
- Tom Uglys Bridge (connecting Blakehurst to Sylvania), for cars, pedestrians and cyclists.
- Como old rail bridge, now for pedestrians and cyclists.
- Como rail bridge on the Illawarra Line, connecting Oatley to Como, for trains.
- Alfords Point Bridge (connecting Padstow Heights to Alfords Point), for cars, pedestrians and cyclists.
- East Hills rail bridge at East Hills, for trains.
- Voyager Point footbridge, for pedestrians and cyclists.
- M5 South Western Motorway Georges River East Bridge
- Newbridge Rd (connecting Moorebank to Milperra), for cars, pedestrians and cyclists.
- Governor Macquarie Drive bridge (connecting Warwick Farm to Chipping Norton), for cars, pedestrians and cyclists.
- Liverpool footbridge (utilises the footing of the decommissioned railway bridge to Holsworthy).
- Newbridge Rd (connecting Liverpool to Moorebank), for cars, pedestrians and cyclists.
- M5 South Western Motorway Georges River West Bridge
- East Hills line rail bridge (connecting Holsworthy to Glendfield), for trains.
- Cambridge Ave Causeway (connecting Holsworthy to Glendfield), for cars.
- King Falls Bridge 
The Georges River is a popular area for recreational fishing. Species present in the river include bream, whiting, yellowtail, jewfish and flathead. The river is also host to a number of commercial oyster farms. The upper ends of the Georges River are abundant with Bass during the summer months and during the winter months these bass migrate down to the lower ends of the river towards the salt water to breed. Waste water inflows to the river are carefully managed to maintain the estuarine habitat.
- "Georges River". Geographical Names Register (GNR) of NSW. Geographical Names Board of New South Wales. Retrieved 4 January 2013.
- Roy, P. S; Williams, R. J; Jones, A. R; Yassini, I; et al. (2001). "Structure and Function of South-east Australian Estuaries". Estuarine, Coastal and Shelf Science 53: 351–384.
- Pollon, Frances, ed. (1990). The Book of Sydney Suburbs. Australia: Angus & Robertson. p. 107. ISBN 0-207-14495-8.
- "Georges River". Estuaries of NSW. Office of the Environment and Heritage. 26 April 2012. Retrieved 4 January 2013.
- "Georges River information page". Campbelltown City Council.
- "Simmo's Beach Reserve". Macarthur Branch: Activities. National Parks Association of NSW. 2011. Retrieved 4 January 2013.
- "Bushwalkers Basin". Macarthur Branch: Activities. National Parks Association of NSW. 2011. Retrieved 4 January 2013.
- "Freres Crossing". Macarthur Branch: Activities. National Parks Association of NSW. 2011. Retrieved 4 January 2013.
- "Liverpool Weir". Heritage Branch, New South Wales waling Department of Planning. Retrieved 24 September 2010.
- "Georges River Bridge". Roads and Traffic Authority, New South Wales. Retrieved 20 September 2010.
- "Kings Falls Bridge over Georges River". Roads and Traffic Authority, New South Wales.