The name Rivendell is derived from archaic English, meaning 'deeply cut valley'. This is also the meaning of its elvish name, 'Imladris', and the Westron name 'Karningul'. The western-most Elven dwelling in Middle-earth during the Third Age, it is known as 'The Last Homely House East of the Sea'.
Set in a deep valley in the foothills of the Misty Mountains, Rivendell was established by Elrond during the Second Age as a refuge and a stronghold in the war again Sauron. The Tale of Years gives the date of its foundation as II.1697, although other texts imply that a dwelling was established there earlier in the Second Age. After Sauron attacked Eregion in II.1695 seeking to seize the Rings of Power, Elrond gathered the surviving elves including the remnants of the Gwaith-i-Mírdain, the elven-smiths of Eregion, who accompanied him to Rivendell.
Through the Third Age, Elrond developed Rivendell as a haven, where people came for rest and council, and as a treasury of lore.
Rivendell continued to be maintained after Elrond departed across the Sea at the end of the Third Age. His sons Elladan and Elrohir remained there for some time, along with their grandfather Celeborn who left Lothlórien after Galadriel passed into the West.
In the Third Age, Rivendell appears as a place in which the spirit of the elves survives, the beauty of their way of life flourishing despite the encroachment of the shadow in other parts of Middle-earth. One important aspect of Rivendell is as place in which the memory of past ages is preserved. The music and singing which delights Sam when the Hobbits visit Rivendell in 'The Fellowship of the Ring' is one way in which stories and memories are maintained and passed on, but also reflects the delight in beauty and the atmosphere of welcome and relaxation that characterise Rivendell. It is a place of rest and refreshment, in which the health and vigour of those who visit is restored.
The drink miruvor is particularly associated with Rivendell - Gandalf calls it "the cordial of Imladris" (The Fellowship of the Ring, Book II, Chapter 3). Elrond gives a flask to Gandalf when the company set out from Rivendell. It is a "warm and fragrent liquor" which provides them with renewed hope and strength when they face the storm on Caradhras.