A refuge and repository set up in the Second Age by Elrond Half-elven. It lay in a hidden vale at the western feet of the Misty Mountains and was called in the Sindarin tongue Imladris, meaning  'Deep Dale of the Cleft'.

Elrond established Rivendell in SA1697  as a refuge from Sauron's war in Eriador. Its situation was further protected by Elrond's posession of Vilya, one of the Three Elven Rings.  His Last Homely House offered shelter to all elves and folk of goodwill including many of the remaining Noldor, and fostered in secret the heirs of Elendil, Chieftains of the Dunedain.

 

As well as being a place of welcome, music, song and good food, Rivendell was a seat of great learning and intellectual endeavour. It was the repository of historical archives and artefacts. Elrond's library held books, documents, maps and artworks from ancient times, and precious artefacts such as scientific instruments, royal regalia, and the shards of Narsil, the sword of Elendil that cut the One Ring from Sauron's hand.

In The Hobbit, Thorin and Company visit Rivendell where Elrond identifies the swords found in the troll hoard and interprets the moon letters on the map of Erebor. Bilbo and Gandalf visit again on their way back to the Shire.

In Lord of the Rings Rivendell hosts the Council of Elrond where The Fellowship of the Ring is formed and Bilbo Baggins who has retired there, sees them set out on their journey.

After Elrond passed over Sea at the end of the Third Age the library and artefacts were moved to the King's restored estate of Annuminas by Lake Evendim but Rivendell endured well into the Fourth Age. Elrond's sons Elladan and Elrohir kept a small establishment there as a haven and way- station on the great east/west route between the Greenwood and theGrey Havens.

NOTE: Additional information from Cirdaneth