Anglicisation of the name, to "Mahon", was never extensive; in 1890 less than 25% of the total recorded their names thus. The current proportion is significantly smaller.
After the defeats of the native Irish in the seventeenth century, many of the Clare MacMahons emigrated to serve in the Irish Brigade of the French army. John Baptiste MacMahon, son of one of the original members of the Irish Brigade in the French army was made Marquis d?Eguilly by Louis XV. His grandson, Edmonde Patrice MacMahon (1808-93) was created Duke of Magenta, became a Field Marshal and President of France. The MacMahon family are still prominent in France; the family home is the Chateau de Sully outside Bordeaux.
.Sir Charles MacMahon (1824-91) , descended from the Clare family, emigrated to Australia in 1853, became Commissioner of Police in Melbourne and secured election to the Legislative Assembly. Another prominent Australian MacMahon was Sir William MacMahon (b. 1908) who was Prime Minister of Australia in 1971 and 1972.
Bernard MacMahon (d.1816) was an emigrant to Philadelphia who became an eminent botanist. His name is recorded in the evergreen shrub berbeeris mahonia.
Charles Patrick Mahon (1800-91), known as "The O?Gorman Mahon", was a member of the Clare family. He was famous as an international soldier - Chile, Brazil, France and Russia are only some of the countries he served - and later as a politician in Parnell?s Irish Party.
Bryan MacMahon(b.1909) has been one of Ireland?s best-loved playwrights and short-story writers for almost 60 years.