The Three Elven Rings were Narya, Nenya, and Vilya and during the War of the Ring they were borne by Gandalf, Galadriel, and Elrond respectively.

After the War of the Ring and the beginning of the Fourth Age, the bearers of the Elven Rings left Middle-earth forever and the power and beauty they had wrought with them diminished.
Encyclopedia entry originally written by Nienna-of-the-Valar