Broken Bay, a semi-mature tide-dominated drowned valley estuary, is a large inlet of the Tasman Sea located about 50 kilometres north of Sydney on the Central Coast of New South Wales, Australia; being one of the bodies of water that separate greater Metropolitan Sydney from the Central Coast. Broken Bay is the first major bay north of Sydney Harbour in the state capital of Sydney.
Broken Bay has its origin at the confluence of the Hawkesbury River, Pittwater, and Brisbane Water and flows openly into the Tasman Sea.
The total surface area of the bay is approximately 17.1 square kilometres.
