Recorded as MacIlheran, MacIlherran, MacKerron, McKerron and McKern, this is a Scottish surname. It is sometimes confused with the Irish McCarron, and there is evidence of a cross integration in Ireland. It is said that this surname was once popular in the Isle of Bute and that one Gillpatrik Mc Kerin held lands in Lanarkshire in the 14h century. An unsupported claim is that a blacksmith called Johan M'Kerin was responsible for the construction of the famous cannon 'Mons Meg.' This huge weapon which still survives, struck fear into its opponents. This was not because of the ferocity of its bombardment, but its sheer size, weighing many tons. This was lucky because otherwise its use was at best limited, and it cracked on almost its first firing! It is unclear when the surname was first recorded as early registers have been lost, and its meaning is open to some argument. We believe that the surname is related to St Ciaran, a 7th century Gaelic holy man, and his name is believed to mean 'Little black'. This surname may originally have described 'The son of the follower of St Ciaran, but there are other possibilities