The Blyth River is a river in the Northern Territory, Australia.
The headwaters rise east of Shadforth Hills and flows in a northerly direction through mostly uninhabited country, past the small community of Gamardi before discharging into Boucaut Bay.
The catchment occupies an area of 9,219 square kilometres and is situated between the Liverpool River catchment to the west, the Goyder River catchment to the east and the Roper River catchment to the south. It has a mean annual outflow of 1,860 gigalitres.
The Cadell and Blyth Floodplains are located at the lower reaches of the river and occupy an area of 432 square kilometres.
The estuary formed at the river mouth is tidal in nature and in near pristine condition.
Many species of fish are found in the river including Sailfin Glassfish, Macleays Glassfish, Barred Grunter, Fly-specked Hardyhead and Pennyfish, Goby, Flathead Goby, Giant Gudgeon, Empire Gudgeon, Threadfin Rainbowfish, Barramundi, Diamond Mullet, Rainbowfish, Western Rainbowfish, Black-banded Rainbowfish, Chequered Rainbowfish, Bony Bream, Black Catfish, Rendahls Catfish, Seven-spot Archerfish.
