The elf queen 0f Shannara - Terry Brooks (Heritage of Shannara #3)

In the Westlands, the elves have disappeared...

Wren Ohmsford, Scion of Shannara, came from the Westlands, where she lived the life of a Rover. Now she, like Par and Walker Boh, has been called upon to help the shade of Allanon fight the totalitarian power of the Federation. She must find the Elves, who disappeared from their strongholds more than one hundred years ago...

No one knew where the elves were - no one except the Addershag, blind, wise woman of the West. On her advice, Wren and her Rover companion, Garth, journeyed to the coast of the Blue Divide, where they built a fire and let it burn for three days. With the unexpected help that their blaze attracted, they reached the isle of Morrowindl and found the last Elves - but they also discovered dangers such as they could not have imagined. And Wren discovered the truth of her past.