A small island near the borders of the Shire. Its exact location is uncertain, but it seems to have been on the lower Withywindle, before the point where it flowed past Grindwall to join the Brandywine at the southern tip of Buckland. It appears in the poem "Bombadil Goes Boating", in which Tom Bombadil sails past the Elvet-isle on his way up the Withywindle to his house in his boat named Old Swan. The island's name seems to be connected to this event; it probably derives from the Old English word for a swan.