There are numerous Irish surnames you’ll hear in America – just one reason why it has such a rich Irish heritage.
Over four million Irish immigrants moved to the United States between 1820 and 1930 during the great plight of the mid-19th century, reducing the population of Ireland by around 25%.
As a result, today we see an enormous amount of Americans claiming Irish heritage – at least 33 million, especially in the historic enclaves of the United States’ northeast where Irish heritage is abundant.
It was once custom for the Irish in America to have a tell-tale “O” before their surnames – this translates as “descendant of” in Gaelic – but this has since mostly disappeared except for a handful of existing popular surnames.
Here are our top 10 Irish surnames you’ll hear in America.
10. Doyle – the dark stranger
Doyle’s roots come from the south-east of Ireland – it is said to be most common in County Carlow, Wexford, and Wicklow. It is derived from the old Irish phrase “Dhubh-ghall”, which translates to “dark stranger”.
This has since led to the traditional belief that the name Doyle was born out of the settlers in Ireland a millennium ago – either Anglo-Saxon settlers from Britain or Danish Norsemen.
9. Fitzgerald – son of Gerald
This name is of Anglo-Norman French origin, and Fitzgerald translates as “son of Gerald.” The Gaelic version is MacGearailt.
It is said that this name originally came from Maurice, son of Gerald, who came to Ireland with powerful archers during the Norman invasions. For his valiant efforts he was awarded land, and his family hence became powerful in County Kildare, although Fitzgerald families were also strong in what is today County Kerry and Limerick.
8. O’Connor – the hound of desire
The O’Connor name has numerous variations and spellings, meaning it’s difficult to point out where exactly it derived from. We know that it originated prominently in five areas of Ireland: Connacht, Kerry, Derry, Offaly, and Clare.
The name was initially spelt O’Conchobhar – a name which goes back to Conchobhar, a 10th-century ruler of Connaught (a kingdom in the west of Ireland).
It once meant something along the lines of “hound of desire” in Gaelic. Unusually for Irish names, the “O” prefix has remained, with more O’Connors than Connors in both Ireland and America.
7. O’Reilly – descendants of Raghaillach
Another Irish name which has kept its “O” – this name has its roots in the old Gaelic kingdom of Breffny, where the O’Reilly family was known as one of the most powerful septs.
Today, this area is known as County Cavan.
The family name is derived from the Irish “O’Raghailligh,” meaning “descendants of Raghaillach”. Raghaillah is said to be born out of compounds ragh (race) and ceallach (sociable).
Reilly, or the shortened Riley, is also a popular first name across the United States.
6. O’Brien – eminent person
This Irish surname you’ll hear in America comes from the O’Brian dynasty, led by Brian Boru who was High King of Ireland from 1002 to 1014. He brought Munster together in times of great unrest and fought for control over the southern half of the Emerald Isle.
Boru’s descendants, the O’Briens, became one of the country’s most important dynasties and have since poured out across the world and into the U.S.
5. Ryan – little king
The meaning of the Irish name Ryan comes from the old Gaelic word “righ” and the old Irish diminutive of “an,” which together roughly translate as “little king” in English.
The O’Riains were most famous in Counties Carlow and Wexford for their authoritative power, and even today continue to frequent the southern half of Ireland more than in the north.
4. Kennedy – fierce head
Known best around the globe as the surname of the U.S. President John F. Kennedy, this ancient Gaelic name was originally spelt “Ceannéidigh”, translating roughly as “fierce head”.
JFK’s family originated from County Wexford, but the name is held most strongly in County Tipperary where the medieval O’Kennedys once inhabited.
Although it is both an Irish and Scottish name, it is the Irish Kennedys who more vehemently flocked to the United States.
3. O’Sullivan – hawkeyed/one-eyed
In Irish, O’Sullivan is spelt O’Suilleabhin. It is widely accepted that this word derives from súl (eye), though whether it is to be translated as “one-eyed” or “hawkeyed” is still in dispute among scholars.
Originally lords in the area of Cahir, County Tipperary, in the 12th century, the O’Sullivans migrated to what is now West Cork and South Kerry, and have since travelled further afield to populate the United States.
2. Kelly – warlike
Kelly, the second most popular Irish surname in the States, is the anglicised form of Gaelic Ó Ceallaigh, or “descendant of Ceallach.” This is an ancient personal name that loosely translates as “bright-headed” or “warlike.”
The name originates from around ten unrelated families and septs across Ireland. These include O’Kelly septs from Meath, Derry, Antrim, Laois, Sligo, Wicklow, Kilkenny, Tipperary, Galway, and Roscommon.
Although seen more commonly as a surname, it is also a particularly popular first name for women in the United States.
1. Murphy – the sea warrior
The most common of all Irish surnames you’ll hear in America is Murphy.
This highly popular surname means “sea warrior”, a personal name that was once particularly popular in County Tyrone. In Irish it translates as MacMurchadh, a derivation of the first name of Murchadh or Murragh.
O’Murchadh families were known to live in County Wexford, Roscommon, and Cork – where it is now most common, with the MacMurchadhs of the County Sligo and Tyrone areas responsible for most of the Murphys in modern-day Ulster.
The name became anglicised first to MacMurphy and then shortened down to Murphy in the early 19th century.
Recognise a lot of these names? The Irish have a huge history of migrating to the United States and make up one of its biggest historical migrant demographics. Since then, Irish Americans have gone on to shape American culture and even change the world.
Check out a list of other Irish surnames you’ll hear in America and elsewhere using our guide.