Rivendell was the realm of Elrond. During the Third Age it was one of the few remaining realms of the Elves in Middle-earth. Much of the history and lore of the Elves was preserved in Rivendell and it was a place of peace and beauty.
On October 25, the Council of Elrond was held at Rivendell to determine what should be done with the Ring. In attendance were several people who had come to Rivendell with news and for counsel including Legolas of Mirkwood, Gloin and Gimli of the Lonely Mountain, and Boromir of Gondor, who had learned in a dream that the shards of Narsil were in Rivendell.
Frodo volunteered to take the Ring to Mordor and destroy it, and a Fellowship of eight companions was chosen to accompany him.
About Elrond
A wise Elf Lord, Elrond is the father of Arwen, and founder and master of the Elf-haven Rivendell. In the Third Age of Middle-earth Elrond is an instrumental leader, rallying the diverse peoples of the lands together to fight the threat of Sauron. When his daughter Arwen contemplates forsaking her immortality to bind herself instead to the Human Aragorn, Elrond's heart is torn between honoring the love of his daughter and losing her to a mortal death. He orders the shards of Narsil to be reforged so that the rightful King of Gondor can reclaim his sword.