Port Curtis is located approximately 95km south of the Tropic of Capricorn on the Central Queensland coast, eastern Australia.
The deep estuarine embayment is bounded by Curtis Island in the north and Facing Island in the south and services the city of Gladstone and surrounding townships of Boyne Tannum and Calliope. Component estuaries, including the larger estuaries of the Calliope and Boyne Rivers, as well as The Narrows and Auckland Creek, merge with deeper waters to form a naturally sheltered, 30km long deepwater harbour. This area contains almost 20,000ha of intertidal wetlands consisting primarily of mangrove communities, saltmarsh habitat and intertidal/subtidal and deepwater seagrass beds. The seagrass habitat in particular is important in supporting vulnerable populations of dugong (Dugong dugon) and green turtles (Chelonia mydas).