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County Cavan

Contae an Chabháin · Ulster
The lake county of Ulster — Shannon source, Gaelic heartland, and the ancestral home of the O'Reilly dynasty

Common Surnames from County Cavan

The most frequent family names with roots in County Cavan — names that spread through Ireland and the Irish diaspora:

O'Reilly Smith Brady Lynch McGovern Farrelly Sheridan McMahon

History & Heritage

Cavan is one of three Ulster counties that remained in the Republic of Ireland after partition — along with Monaghan and Donegal. It sits in the drumlin belt, that undulating landscape of small rounded hills and innumerable lakes left by the retreating glaciers. The county has over 365 lakes — one for every day of the year, locals claim.

The River Shannon, Ireland's longest river, rises at the Shannon Pot in the Cuilcagh Mountains in the northwest of County Cavan. The source of the Shannon in Cavan — and the river's subsequent journey 360 kilometres to the Atlantic — represents one of the great natural heritage features of Ireland.

O'Reilly is the definitive Cavan surname. The O'Reillys were the ruling family of the ancient kingdom of Breifne, which covered most of Cavan and Leitrim. Their power lasted from the ninth century until the Plantation of Ulster in the early seventeenth century. The name derives from Ó Raghallaigh — 'descendant of Raghallach.'

The County Cavan Diaspora in America

Cavan emigrants were a significant part of the Ulster Protestant and Catholic migration to America. The county's border position and mixed religious heritage meant its emigrants came from both traditions. New York, in particular, absorbed large numbers of Cavan families.

Stay Connected to County Cavan

Love Ireland covers Cavan's lake landscapes, the Shannon source, and the drumlin country that stretches across the Ulster border. The county is quieter than its west-coast equivalents — and more rewarding for it.

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Researching Your County Cavan Ancestry

If your family came from County Cavan, here's where to start your research:

Notable People from County Cavan

Related Irish Surname Guides

Common County Cavan surnames with dedicated pages on this site:

Oreilly Brady Lynch Smith