The McArthur River is a river in the Northern Territory of Australia which flows into the Gulf of Carpentaria at Port McArthur, opposite the Sir Edward Pellew Group of Islands. The river was named by Ludwig Leichhardt while he explored the area in 1845. He named the River after James MacArthur and the MacArthur family of Camden, who were enthusiastic supporters of his expedition. The McArthur River has significance for the local Aboriginal communities, who use it for fishing and other traditional activities.

The Northern Territory is an Australian territory in the central and central northern regions of Australia. The Northern Territory shares its borders with Western Australia to the west, South Australia to the south, and Queensland to the east. To the north, the territory looks out to the Timor Sea, the Arafura Sea and the Gulf of Carpentaria, including Western New Guinea and other islands of the Indonesian archipelago.