Tomago is a combined industrial/semi-rural suburb of the Port Stephens local government area in the Hunter Region of New South Wales, Australia. It is located just north of the Hunter River and west of the body of water known as Fullerton Cove. Tomago means "sweet water" in the local Aboriginal language. In 2016 277 lived in Tomago with a median age of 55, 72.7% born in Australia and 80.4% only speaking English at home.

The Hunter River is a major river in New South Wales, Australia. The Hunter River rises in the Liverpool Range and flows generally south and then east, reaching the Tasman Sea at Newcastle, the second largest city in New South Wales and a major harbour port. Its lower reaches form an open and trained mature wave dominated barrier estuary.