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.

[3] It has a mean annual outflow of 1,860 gigalitres (2.433×109 cu yd),[4] The Cadell and Blyth Floodplains are located at the lower reaches of the river and occupy an area of 432 square kilometres (167 sq mi).

The estuary formed at the river mouth is tidal in nature and in near pristine condition.

[5] The river was named by Francis Cadell in 1867 after the Premier of South Australia, Arthur Blyth.

[1] David Lindsay charted the river in 1883 during his expedition of Arnhem Land.