I asked a question yesterday about why the Lonely Mountain and the Dwarves weren't featured in The Lord of the Rings, and I got answers explaining how they were in their own battle. But if that was so, then surely Gimli son of Glóin wouldn't have been in attendance at the Council of Elrond in Rivendell?
Because the battle had not started yet, they looking for advice on what to do about the emissary from Sauron, and hoping for news about the attempt to recolonize Moria.
Why couldn't a single dwarf be elsewhere, even if other dwarves are fighting battles?
The dwarves of Erebor are worried, because nobody has heard anything from Moria for a long time after Balin went to reclaim it, and because of a messenger from Sauron who has come to them asking about rings and hobbits, and making veiled threats. So they send Glóin (the same one from The Hobbit) to Rivendel to warn Bilbo and get advice from Elrond. This is Glóin speaking, at the Council of Elrond:
'Then about a year ago a messenger came to Dáin, but not from Moria—from Mordor: a horseman in the night, who called Dáin to his gate. The Lord Sauron the Great, so he said, wished for our friendship. Rings he would give for it, such as he gave of old. And he asked urgently concerning hobbits, of what kind they were, and where they dwelt. "For Sauron knows," said he, "that one of these was known to you at a time."
'And so I have been sent at last by Dáin to warn Bilbo that he is sought by the Enemy, and to learn, if may be, why he desires this ring, this least of rings. Also we crave the advice of Elrond. For the Shadow grows and draws nearer. We discover that messengers have come also to King Brand in Dale and that he is afraid.
Gimli is in Rivendel accompanying Glóin, his father. When the Fellowship of the Ring is formed, Elrond volunteers Gimli to go with them to help Frodo and represent the dwarves.