Family name Mc Granaghan (Mc Granaghan 
) , all over the world, is a very rare cognomen. The surname Mc Granaghan is habitual in Ireland, where it is a rare surname, New Zealand, where it is a very rare surname, and the United Kingdom. Not in comparison with a country's population, it is commonest in Ireland, the United Kingdom, and Germany.
| VARIANT | COUNTRY |
|---|---|
| Mc Granaghan | Germany, United Kingdom, Ireland, United States, New Zealand |