The longest river in Middle Earth, according to J.R.R. Tolkien's Lord of the Rings series is the Anduin. In Sindarin, the language Tolkien made up for the books, Anduin means "great river."Andwyn
this name is from The Hobbit and was the name of a great river in middle world. I used the name Andwyn for a character in a children's book I wrote.)
The longest river in Middle Earth, according to J.R.R. Tolkien's Lord of the Rings series is the Anduin. In Sindarin, the language Tolkien made up for the books, Anduin means "great river."