River Trolls are a type of troll never actually mentioned in J.R.R Tolkien's writings. The idea that Tolkien wrote about them arose from a misreading of the text in The Hobbit. As the Dwarves enter Lake-town, the narrative mentions "occasional squabbles about river-tolls" between the men of Lake-town and the nearby elves. In other words, squabbles over whether the elves or the men could collect (or had to pay) tolls for passing down the river. Some readers mistakenly read the word tolls as trolls, thereby imagining entirely new creatures called "River-trolls" that Tolkien never intended.