The Po river
Po
There are two rivers in Switzerland which have three letters in their names. The river Aar and the river Inn
The River Nile has only four letters.
River Trent.
I think the longest name has 32 letters which is Bernadette Maria Rosena McLaughclin.
The Kalamazoo River.
No
The Rodil is a Spanish river with five letters.
axe
danube
Rio
Exe
ural