As if it were not confusing enough to have contradicting definitions and spellings of the name “Kennedy,” additional confusion arises because the name appears not only in Scotland but also in Ireland. Why is that and who can lay claim to “Kennedy”? The answer is that Kennedy as a name and clans are both Irish and Scottish , yet developed independently of each other.
Though they share a similar language in Scots Gaelic and Irish, Ireland and Scotland also share a Gaelic heritage in that the Kingdom of Dal Riada (founded 5th century, allegedly by Fergus Mor) existed in both Ulster and across the North (or Irish) Channel in Argyll (Airer Goidel, “coast of the Gaels”). These seafaring settlers were Irish Gaels, also known to the Romans as Scoti, and as Gaelic speakers they were much different than those in the rest of what is now known as Scotland, and they were Pictish or Brittonic speakers. It was these people that helped to Christianize Scotland, especially in Iona. Kilmartin Glen seems to also have been a stronghold of Dal Riadic sites. Eventually, the Ulster portion fell into chaos due to the competing claims between the Dal Riada and their rival the Dal nAraidi. This chaos in turn allowed the Ui Neill to become the dominant power in Ulster. In Scotland, the Dal Riada eventually merged with the Picts, uniting under Kenneth MacAlpin (Cinead mac Ailpin) in 843CE. This union was the Kingdom of Alba, the forerunner of Scotland.
The Kennedys in Scottish history appear around 1100CE in Carrick and became a powerful family in southwestern Scotland. However, some Kennedys also made it to Perth and Lochaber. Regardless, the Scottish Kennedys and Irish Kennedys were separate of each other.
The Irish Kennedys are said to have arisen from the nephew of Brian mac Cennetig, High King of Ireland (and better known as Brian Boru) whose name was Cinni’eide. To further confuse things, the name can mean either “grandson of Cennitig” or “Helmet-headed”. Regardless, the Irish Kennedys became the Lords of Ormond from the 11th to 16th centuries. Ormond consisted of territory in what is now Tipperary and parts of Kilkenny and Waterford. The famous Kennedy family of the U.S. hails from Wexford.
To further complicate things, numerous Kennedys emigrated from Ayrshire and Galloway to Northern Ireland, either independently or as part of the Plantations. These Kennedys became part of what are collectively known as Ulster Scots or Scots Irish, who later left in great numbers for British North America. Many U.S. presidents can trace their lineage to Ulster, and it was this group that had an active role in the settling of the frontiers of the colonies and achieving independence for the United States. In fact, there were seven Overmountain Kennedys who fought at King’s Mountain, North Carolina in 1780 against Loyalist militia.
An interesting point of reference is that the surname Kennedy ranks as the 16th most common in Ireland, 58th in Scotland, 137th in the U.S., and 163rd in England and Wales. In Australia it ranks 70th, in New Zealand it ranks 98th, and in Canada 82nd.