Save on Family Finder, Y-DNA, and mtDNA During Our Annual Summer Sale! Now through August 31st.

Clancy Surname (DNA) Project

  • 126 members

About us

Before this Y-DNA project was established, it was already known that the Irish surname Clancy, originally MacClancy and in Irish Mac Fhlannchaidh or Mac Fhlannchadha, had at least two separate origins.  One sept, in Thomond (now County Clare), were hereditary brehons to the O'Briens.  The other was of Rosclogher in County Leitrim.

The Thomond sept has given its name to three townlands in County Clare:
The best account of the Thomond sept is "The Síol Fhlannchadha of Tradraighe, Co. Clare: Brehon Lawyers of the Gaelic Tradition" by Luke McInerney in volume 9 (2016) of Eolas: The Journal of the American Society of Irish Medieval Studies.

The best account of the Leitrim sept is Historical notes on the ancient sept of Clancy, Glancy (MacFhlannchadha) of Dartry, compiled by Maria Clancy (Dublin: Linden Publishing Services, 2007) (ISBN: 9781905487080).

Early DNA results have shown that the Clancy surname actually has at least six different genetic origins.

The name has spread from Clare and Leitrim throughout Ireland and abroad.  The 1911 census of Ireland included 3,632 Clancys, 653 of them born in County Clare and 573 in County Leitrim.