AILSA, an island belonging to the parish of Dailly, in the district of Carrick, county of Ayr. This island lies in the Firth of Clyde, between the shores of Ayrshire and Cantyre, from the former of which it is distant eight miles. It is a rugged rock, about two miles in circumference at its base, rising precipitously from the sea to an elevation of 1100 feet, and accessible only on the north-east side, where a small beach has been constructed. The rock is basaltic, and in several parts assumes the columnar formation: at a considerable height are the remains of ancient buildings, supposed to have been originally a castle, with a chapel. A small portion of its surface affords a scanty pasturage; but it is frequented merely by various aquatic birds, of which the most numerous are the solan geese; and the only income arising from the island is derived from the sale of feathers, for the collection of which, during the season, a person resides on the spot. It was in contemplation, some time since, to make this island a fishing station, for the supply of Glasgow and Liverpool by the numerous steamers which pass this way, and the erection of some buildings for that purpose was commenced, but the idea was subsequently abandoned. The island gives the British titles of Marquess and Baron to the family of Kennedy, who are the owners of the property. It is mentioned by the poet Burns in his song of Duncan Gray.