The elven refuge founded by Elrond in J.R.R. Tolkien’s The Lord of the Rings is Rivendell.
Rivendell is also called Imladris, a Sindarin name meaning “deep valley of the cleft.” Elrond established it in the Second Age after the destruction of Eregion, and it remained an important refuge for Elves and the descendants of the Númenórean kings.
In The Lord of the Rings, Frodo reaches Rivendell after being wounded by a Nazgûl. Elrond heals him, and the Council of Elrond later decides what should be done with the One Ring. The Fellowship of the Ring is formed there before the company leaves on its journey.
Rivendell is distinct from Lothlórien, the woodland realm ruled by Galadriel and Celeborn. Gondolin is another elven city, but it belongs to the much earlier First Age.