The ground now became damp, and in places boggy and here and there they came upon pools, and wide stretches of reeds and rushes filled with the warbling of little hidden birds. They had to pick their way carefully to keep both dry-footed and on their proper course. At first they made fair progress, but as they went on, their passage became slower and more dangerous. The marshes were bewildering and treacherous, and there was no permanent trail even for Rangers to find through their shifting quagmires. The flies began to torment them, and the air was full of clouds of tiny midges that crept up their sleeves and breeches and into their hair.
- The Fellowship of the Ring (Book 1), Chapter 11
Located between the Chetwood and the Weather-hills, the Midgewater Marshes are a fly-infested fen.