Ossiriand
Ossiriand, "the Land of Seven Rivers", was a region of eastern Beleriand, lying between a great river in the west, and the Ered Luin in the east. Six of the river's tributaries flooded east to west, defining Ossiriand's north and south borders. It was a green, wooded country known for its many elm trees. Following the War of Wrath and the drowning of Beleriand, Ossiriand survived as the western portion of Middle-earth and was thereafter known as Lindon.
History
In the early First Age, before the rising of the Moon, a host of the Nandor led by Denethor crossed the Ered Luin from the east and settled in Ossiriand with Thingol’s leave. They wore raiments dyed green. Skilled in woodcraft, they could remain unseen by travelers in their lands. When Thingol called upon Denethor for aid in the first battle of Beleriand, the High Elves of Ossiriand marched to war. Lightly armed, they were ill-prepared for battle with Orcs, and Denethor himself was slain. After that time the elves of Ossiriand abandoned open warfare, withdrew into secrecy, and never again chose a lord.
During the time of the Long Peace, Finrod Felagund entered Ossiriand, befriending the elves living on the land. On one of his journeys he discovered the Race of Man dwelling there. At the request of the Ossiriand elves, he advised them to remove to Estolad, which they did. Though Ossiriand suffered little directly from the great battles of Beleriand, many Elves fled there after the Battle of Sudden Flame. Some of Fëanor's sons maintained watch upon a hill just west of Ossiriand with support from the local elves, and Orcs seldom entered Ossiriand.
After the return of Beren and Lúthien, they dwelt on an island in the southernmost of Ossiriand's streams. Later, when the Dwarves of Nogrod attempted to return home with the treasure of Doriath, they were ambushed by Beren and an army of Ossiriand elves, and the treasure was cast into the northernmost river. At the end of the First Age, the War of Wrath brought the ruin and submersion of Beleriand. Much of the land sank beneath the Sea, but Ossiriand and parts of the Ered Luin remained above the waters. With the Sea breaking through the mountains to form the Gulf of Lhûn, Ossiriand endured under the new name Lindon, the last remnant of Beleriand in Middle-earth.
Etymology
The Sindarin name Ossiriand derives from os- (“around, about”) and sîr (“river”), referring to the seven rivers of the land. It was rendered “Land of Seven Rivers.” The later name Lindon means “Land of Music,” recalling the song of the High Elves of Ossiriand.