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 (360 mi) 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.