Which river is the longest that ends in an inland delta?

The Okavango is the longest river that ends in an inland delta. Instead of reaching an ocean, it spreads into the Okavango Delta in Botswana, where its water disappears into desert sands, wetlands and seasonal channels.

The river begins in the highlands of Angola, where it is known locally as the Cubango, then flows through Namibia before entering Botswana. Its course is roughly 1,600 to 1,700 kilometres long. In the Kalahari Basin, the river loses elevation across an exceptionally flat landscape and fans out into a vast alluvial wetland.

The annual flood is unusual because it arrives during Botswana's dry winter. Rains fall in Angola around January, but the flood takes months to travel downstream, usually reaching its greatest extent between June and August. The delta can expand to about three times its permanent size, supporting elephants, hippos, crocodiles and huge concentrations of birds.

Unlike a conventional delta, the Okavango has no permanent outlet to the sea. In exceptionally wet years, small flows may escape toward the Boteti or Zambezi systems, but the river normally terminates within the inland delta.