The Hawkesbury River, or Hawkesbury-Nepean River, 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. 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.
Aerial photograph showing the mouth of the Hawkesbury River as it flows into Broken Bay and out into the Tasman Sea, as seen looking across Sydney's Northern Beaches