|Other names||Gwathir, Greyflood|
|Location||Border between Minhiriath and Enedwaith|
|Description||Broad navigable waterway originally bordered by trees|
|Events||Battle of the Gwathló|
The Gwathló, also known as Greyflood and previously known as Gwathir, was the name of the river separating Minhiriath from Enedwaith. It began at the confluence of the rivers Mitheithel (Hoarwell) and Glanduin, from whence it flowed south-west until it emptied into the Great Sea at Lond Daer. The only crossing point was at Tharbad.
 The Second Age
Aldarion, the son of Tar-Meneldur, was the first Númenórean to find the mouth of the Gwathló. After the king forbade the cutting of trees in Númenor, Aldarion established a haven called Vinyalondë or "New Haven" at the mouth of the river the Númenóreans called the Gwathir, or "River of Shadow". There Númenórean ships could be repaired and men could go forth and cut timber.
When explorers from Aldarion's ship ventured up the river in small boats they found huge trees overshadowing the waters. They thus named the river the Gwath-hîr ("Shadow-river") which became Gwathir. However, later when the Númenóreans penetrated further up the river they found great fens, the Nîn-in-Eilph or "Swanfleet". Mistakenly believing that the fens were the source of the river they changed the name of the waterway to Gwathló, where the lô meant fenland and thus the new name meant the "shadowy river from the fens". This Sindarin name was translated into Adûnaic as Agathurush.
The lumbering activities of the Númenóreans began along the banks of the Gwathló so that the timber could be floated downstream to the haven. Wanting more wood for their ships the Númenóreans cut great roads into the forests north and south of the river, which aroused the enmity of the scattered forest dwellers. These people attacked the Númenóreans but they were driven away, either north-west into the Eryn Vorn or south-east into Dunland. Eventually the lands along the Gwathló became denuded of trees. As more Númenórean settlements were established in Middle-earth the name of Vinyalondë was changed to Lond Daer, or in full Lond Daer Enedh, the "Great Middle Haven".
In S.A. 1695 Sauron's forces invaded Eriador and by 1699 he had overrun the region. He pressed on with the intention of taking Lindon while leaving a powerful detachment to contain Elrond in Rivendell. Unbeknownst to the Dark Lord in 1695 Gil-galad had sent messages to Númenor requesting aid. The great fleet of Tar-Minastir arrived in 1700 and the Númenóreans and the Elves drove Sauron back from the river Lhûn and pushed him further back from the Baranduin. Worse for Sauron was to follow, for the Númenórean admiral Ciryatur had sent a host to Lond Daer and they attacked the rear of Sauron's army. In the Battle of the Gwathló Sauron was heavily defeated and escaped with but a small bodyguard.
 The Third Age
During the time of the Númenóreans the ford below the Swanfleet had merely marked the end of navigation. However, after the establishment of the Kingdoms of Arnor and Gondor a great bridge was built at this point so that the North-South Road could connect the two realms. Tharbad arose as a garrison town of soldiers, mariners and engineers. The town lasted until the Great Plague of T.A. 1636, after which it fell into swift decay.
The bridge at Tharbad long remained intact, but in 2911 the Fell Winter froze the river and in 2912 great floods ruined Tharbad and it became deserted. In T.A. 3018 when Boromir came to Tharbad he found only a dangerous ford and in crossing lost his horse.
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), Unfinished Tales, "The West of Middle-earth at the End of the Third Age" [map]
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), Unfinished Tales, "Aldarion and Erendis: The Mariner's Wife"
- ↑ 3.0 3.1 J.R.R. Tolkien, Christopher Tolkien (ed.), Unfinished Tales, "The History of Galadriel and Celeborn", "Appendix D: The Port of Lond Daer"
- ↑ J.R.R. Tolkien, The Lord of the Rings, Appendix B, "The Second Age"
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), Unfinished Tales, "The History of Galadriel and Celeborn", "Concerning Galadriel and Celeborn"
- ↑ 6.0 6.1 J.R.R. Tolkien, The Lord of the Rings, Appendix B, "The Third Age"
- ↑ J.R.R. Tolkien, The Lord of the Rings, Appendix A, "The Númenorean Kings", "Eriador, Arnor, and the Heirs of Isildur"
- ↑ J.R.R. Tolkien, The Lord of the Rings, The Fellowship of the Ring, "The Council of Elrond"