Ailsa Craig (Scottish Gaelic: Creag Ealasaid) is an island of 219.69 acres in the outer Firth of Clyde, 10 miles from mainland Scotland, upon-which blue hone granite was quarried to make curling stones. The now uninhabited island is formed from the volcanic plug of an extinct volcano.
The island, colloquially known as "Paddy's milestone", was a haven for Catholics during the Scottish Reformation in the 16th century, but is today a bird sanctuary, providing a home for huge numbers of gannets and an increasing number of puffins.
The island is owned by The 8th Marquess of Ailsa, but since May 2011 has been up for sale. By March 2013 the asking price was for offers over £1,500,000, down from the original asking price of £2,500,000. <ref>BBC News (21 March 2013). "Ailsa Craig: Asking price reduced in Irish Sea island sale". (accessed 23rd May 2013)</ref> In December 2013 it was reported that the island had been sold to an enviromental trust. <ref>http://www.theguardian.com/uk-news/2013/dec/07/ailsa-craig-gannets-puffins-clyde (accessed 29th May 2014</ref>
An early reference to the rock is made by Sir Donald Monro, Archdeacon of the Isles who referred to the rock as "Elsay" in the 16th century. <ref>Monro, Sir Donald (1549) A Description Of The Western Isles of Scotland. Appin Regiment/Appin Historical Society. Retrieved 3 March 2007. First published in 1774 </ref>
The modern name of the island is an anglicisation of the Gaelic, Aillse Creag meaning "fairy rock". <ref>Iain Mac an Tàilleir (2003). "Placenames" (PDF). Pàrlamaid na h-Alba. Archived from the original on 21 August 2010. Retrieved 23 July 2010</ref>
An alternative Gaelic name is Creag Ealasaid meaning "Elizabeth's rock".<ref>Haswell-Smith, Hamish (2004). The Scottish Islands, 3</ref>
The first element, Aillse may represent Allt Shasann, "cliff of the English", mentioned in the Book of Leinster as Aldasain.
The island is sometimes known as "Paddy's Milestone", being approximately the halfway point of the sea journey from Belfast to Glasgow, a traditional route of emigration for many Irish labourers coming to Scotland to seek work.
As a result of being the most conspicuous landmark in the channel between Ireland and Scotland, the island is known by a number of different names;
A' Chreag: "the rock" Creag Alasdair: "Alasdair's rock" Ealasaid a' Chuain: "Elizabeth of the ocean" Alasan Carraig Alasdair: "Alasdair's Rock" (used in the Madness of Sweeney, the tale of a legendary king of Ireland). The Bass Rock is sometimes nicknamed "the Ailsa Craig of the East", although its prominence in the Firth of Forth is not as great as that of Ailsa Craig in the Firth of Clyde