The Hawkesbury River is a semi-mature tide dominated drowned river valley located to the north and west of Sydney. It is part of a larger more complex river system known as the Hawkesbury-Nepean Catchment, which is one of the largest coastal basins in NSW. 

The catchment area is approximately 21,400 square kilometres and it includes a number of major rivers and tributaries including the Hawkesbury-Nepean, Colo, Coxs, Grose, McDonald, Wollondilly and Warragamba rivers. 

The Hawkesbury River and its estuary has great social, environmental and economic significance to many communities in the Sydney and Central Coast regions. As well as the ongoing relationship traditional owners have with the river system, many local people have strong historical and cultural ties to the river dating back to early colonial Australia. The river, estuary and its tributaries support a diverse ecosystem including riparian vegetation, wetlands, mangroves, saltmarshes and tidal mudflats which provide habitat for a diverse array of flora and fauna. It's used for a variety of recreational pursuits, including fishing, boating, swimming, canoeing/kayaking, bushwalking, camping and birdwatching. The rivers and dams within the catchment provide the majority of Greater Sydney's drinking water and the system supports a 259 million dollar agriculture industry. Other commercial activities occurring within the river system include boat hire and charters, short term holiday rental properties, oyster farming and commercial fishing.