Lake Macquarie is Australia's largest coastal lagoon. Located in the City of Lake Macquarie and Central Coast Council local government areas in the Hunter and Central Coast regions of New South Wales, Australia, it covers an area of 110 square kilometres (42.5 sq mi) and is connected to the Tasman Sea by a short channel. Most of the residents of the City of Lake Macquarie live near the shores of the lagoon.

The City of Lake Macquarie is a local government area in the Hunter Region in New South Wales, Australia. It was proclaimed a city from 7 September 1984. The city is situated adjacent to the city of Newcastle and is widely considered as a part of the Greater Newcastle area. The city is approximately 150 km (93 mi) north of Sydney. One of its major tourist attractions is its lake, also named Lake Macquarie.