Cognomen Cathasaigh (Cathasaigh 
) , in all the world, is a very rare surname. The family name Cathasaigh is habitual in Northern Europe, particularly Ireland, where it is a rare surname.
| VARIANT | COUNTRY |
|---|---|
| Cathasaigh | Ireland |
|
seán ó cathasaigh Irish writer (1880-1964), IE (b. 1880) |
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marc ó cathasaigh Irish Green Party politician, IE (b. 1977) |
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| tomás ó cathasaigh IE (b. 1942) |
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| matthaeus mac cathasaigh Irish priest |
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| aindrias ó cathasaigh historian |
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| nicolaus mac cathasaigh Priest and bishop in Ireland (died 1356) |
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