Ailsa Craig is a prominent island roughly midway between Glasgow and Belfast, so it is also called Paddy’s Milestane.

The island is composed of Microgranite with dykes of Microgabbro, the castle walls include some sandstone!

The castle was built around 1400/1500.

Rock from the island was used to make curling stones. The rock from the south was used for the bulk of the stone, rock from the north was used for the base which is in contact with the ice. Stones made from Ailsa Craig rock have been used recently in the Olympics.

The Stevensons’ lighthouse on the east side was completed in 1886. Fog signals (horns) were erected in the north and south ends of the island.

Communication with the mainland was by pigeons. If a doctor was needed in stormy conditions a fire was used to alert those on the mainland.

Gannets nest in large numbers on Ailsa Craig.