Where the Clancy surname comes from, how the Clare Clancys served Brian Boru’s descendants as judges, the unrelated Leitrim Clancys, and which DNA test tells them apart.

The Clare Clancys (Mac Fhlannchaidh, “son of Flannchadh”, the ruddy warrior) were a branch of the MacNamaras and the hereditary brehons, or judges, of the O’Brien kings of Thomond. They held land at Knockfin and Cahermaclancy in north-west Clare, in the barony of Corcomroe. A second, unrelated Clancy family ruled Dartry in County Leitrim.

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Clare Clancy or Leitrim Clancy?

Two unrelated Clancy families share the name, and only the Clare family belongs to Brian Boru’s kindred. A Y-DNA test tells you which one is yours. Family Tree DNA is the only major testing company with dedicated Y-DNA tests, and it hosts both the Clancy surname project and the R-L226 project.

• Y-37: shows whether your paternal line fits the Irish Type III (R-L226) pattern.
• Big Y-700: places you on a specific branch of the tree, the test that project administrators recommend.
• Family Finder: covers all your family lines, not just the male line, and finds cousins from the last five or six generations. Women can take it too.
• Free projects: once tested, join the Clancy surname project and the R-L226 project to compare results.

Order the Y-37 testSee Big Y-700Family Finder (women and all lines)

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Origin of the name

Patrick Woulfe records two families called Mac Fhlannchadha. The Thomond family was a branch of the MacNamaras, which makes the Clare Clancys part of the Dál gCais and distant cousins of Brian Boru. The other family were chiefs of Dartry, now the barony of Rosclogher in County Leitrim, with no connection to Clare.

Brehons to the O’Briens

In Gaelic Ireland the brehon was the lawyer and judge who interpreted the native law for his lord. The office passed down within learned families, and in Thomond it belonged to the MacClancys for centuries. The annals record their chief brehons by name: Aedh Mac Fhlannchaidh, ollamh of Thomond, died in 1492, ten years after his chosen successor Murchadh. The family’s lands at Cahermaclancy and Knockfin lie in the stone-walled country between the Burren and the Atlantic, close to Lisdoonvarna and the Cliffs of Moher.

The family kept their standing after the Gaelic order fell. In 1588 Boetius Clancy was sheriff of Clare when Spanish Armada ships were wrecked on the county’s coast, and local tradition still remembers him for the execution of the survivors.

Clancy DNA

The Clancy Y-DNA project on Family Tree DNA was set up because the name was already known to have at least two origins. A Clare Clancy who belongs to the MacNamara branch should carry R-L226 (Irish Type III), the Dál gCais marker, while a Leitrim Clancy will not. A Y-37 test from Family Tree DNA separates the two, and Big Y-700 shows how close you sit to the MacNamaras. For a Clancy grandmother or any line other than your direct paternal one, use Family Tree DNA’s Family Finder. Our DNA guide explains how to read the results.

Clancy places to visit

• Cahermaclancy and Knockfin: the brehons’ townlands in north-west Clare, on the edge of the Burren.
• Cliffs of Moher: a short drive from the Clancy lands. Book a Cliffs of Moher tour.
• Ennis: the county town and the base for Clare research. See places to stay around Quin and Ennis.
• Killaloe: the seat of the O’Brien kings the Clancys served. Plan it with our Brian Boru trail.

Related Dál gCais surnames

See the MacNamaras and McInerneys, another MacNamara offshoot, the McGraths, poets to the same O’Brien court, and the Considines, or browse all Brian Boru kindred surnames.

Frequently asked questions

Is Clancy an Irish name?

Yes. Clancy is the anglicised form of Mac Fhlannchaidh, borne by two unrelated Gaelic families in Clare and Leitrim.

Are the Clancys related to Brian Boru?

The Clare Clancys are. They were a branch of the MacNamaras, so they are distant Dál gCais cousins of Brian Boru. The Leitrim Clancys are unrelated.

What did the Clancys do?

The Clare Clancys were the hereditary brehons, or judges, of the O’Brien kings of Thomond.

What does the name Clancy mean?

It means “son of Flannchadh”, a personal name glossed as ruddy warrior.

Sources

1. Patrick Woulfe, Irish Names and Surnames: Mac Fhlannchadha (1923).
2. Family Tree DNA, Clancy Surname Project: background.