Blue Mud Bay is a large, shallow, partly enclosed bay on the eastern coast of Arnhem Land, in the Northern Territory of Australia, facing Groote Eylandt on the western side of the Gulf of Carpentaria. It lies 580 km east-south-east of Darwin in the Arnhem Coast bioregion. Its name was given to a landmark court ruling affirming that the Aboriginal traditional owners of much of the Northern Territory\'s coastline have exclusive rights over commercial and recreational fishing in tidal waters overlying their land.
The bay is about 90 km in length and up to 35 km in width. Its 45 km wide mouth stretches from Cape Shield in the north-east to Cape Barrow in the south-west, with Woodah Island in between. It has a diverse inner coastline of many small bays, inlets, headlands and islands, bordered by intertidal mudflats and mangroves merging into freshwater floodplains. The bay and the adjoining floodplains are held by the Arnhem Land Aboriginal Land Trust as Aboriginal freehold land. The waters of the bay are used for commercial and recreational fishing, especially for mud crabs. The northern part of the bay and its surrounds are part of the Laynhapuy Indigenous Protected Area, which is planned to be extended to include the remainder of the coastal waters and islands of the bay.
