Irish Last Names Beginning With K (With Meanings)

Are you interested in the origins and meaning of an Irish last name that begins with K?

This article lists Irish surnames that had birth registrations in early 20th century Ireland and also appear in the 2010 American census.

We’ll also give the origins and meanings of the most popular names.

Most Common Irish Surnames Starting With K

Let’s start with Irish names that had at least eight hundred births in Ireland between 1923 and 1932.

We’ve also included the numbers in the 2010 U.S. census. Bear in mind that many names have different origins and are from different regions.

So, King may be the descendants of Irish ancestors and have one meaning. But other families may descend from English ancestors with different origins.

Last NameBirths2010 Census

Why take Irish birth registrations from 1923 to 1932?

The second column is the number of Irish birth registrations over ten years starting in 1923.

The reason I chose that start date was that the Republic of Ireland was established the previous year. Starting in 1923 excluded birth locations in Northern Ireland.

Otherwise, I would have a lot of work filtering out English and Scottish names for this list.

Origins And Meanings Of Irish Surnames Starting With K

Let’s run through the origins and meanings of these top names.


Kelly was the most common name in Ireland back in the early 1920s and it remains so to this day.

This is an Anglicized form of the Gaelic name Ó Ceallaigh. I explain “Anglicization” more fully in a later section.

Here, I’ll simply say that it’s a way of taking an old Gaelic surname and turning it into a name that sounds or seems English.

The “Ó” in Ó Ceallaign means “descendant of”, so this name means the descendant of Ceallach.

So, who was Ceallach? Interestingly, there are three different theories for the original meaning of the name.

The Irish scholar Patrick Woulfe wrote in 1923 that “ceallach” referred to an old Irish word meaning war or contention.

Others say that it refers to the word for bright or bright-headed (fair-haired). In modern Irish, the word geal means bright.

A third theory is that the meaning comes from the Irish word ceaill and refers to someone who often visits churches.

All these theories could be correct. In other words, the name could have been conferred on different people for different reasons in different parts of Ireland.

There were several prominent clans with an O’Kelly as chief.

One kingdom in what is now the province of Connacht was ruled for centuries by an O’Kelly clan. Tadgh Mór Ó Ceallaigh (Big Tadgh O’Kelly) was the 36th king of his territory.

This O’Kelly made an alliance with Brian Boru, the High King. He fought and died at the Battle of Clontarf in 1014 when Irish clans fought the Danes (and their Irish allies) on the seafront.

Battle of Clontarf, 1014


This is an Anglicized form of the Gaelic name Ó hÍceadh, or descendant of Ceannéidighe.

There are several theories for the meaning. There is general agreement that the first part of the name comes from the Irish word for a head (ceann).

The latter part could derive from the Irish word for ugly or for a helmet. So, it could have been the helmet-headed man or the man with an ugly head.


This is an Anglicized form of the Gaelic name Caomhánach. The “ach” at the end means “belonging to”, so it refers to “belonging to Caomhán”.

Caomhán is a personal name that refers to a beautiful or handsome person. The English version is Kevin.

Several generations of the early Kavanagh families were Kings of Leinster. You can read about the rich history in this article on the Kavanagh clan.


This is an Anglicized form of the Gaelic name Ó Coinnigh, or descendant of Coinneach (or Cainneach). This meaning refers to someone who is handsome.

A renowned early saint named Cainneach was an abbot during the early Middle Ages. Born in Ulster, he travelled to Scotland, Wales, and Rome. He is known in Scotland as Saint Kenneth.

In Ireland, the town of Kilkenny is named after him (it literally means the church of Kenny).

The legend goes that the last Archdruid in Ireland had fled from the rise of Christianity to what is now known as Kilkenny. Cainneach marched on the area with an army and that was the end of the druids!

As an aside, he is also the patron saint of the shipwrecked.

Keane and Kane

These two Irish names are variants of each other. They were taken as the Anglicized version of several Irish family names.

The Gaelic name Ó Catháin, or descendant of Cathán, takes its meaning from the Irish word for a battle (cath).

The name Ó Céin, or descendant of Cian, takes its meaning from the words for a long distance.


This is one of those names that arose in different regions with different origins. Families in the United States may descend from ancestors in England are from across Europe.

The Irish name is a translation of the word for a king (). So, the English name was taken by families who had some form of the Irish word in their Gaelic name.

O Rian is one example, with Rian meaning “little king”. Some families could have Anglicized this by meaning to King.

However, this name was perhaps more often Anglicized phonetically to Ryan.


This is an Anglicized version of the Gaelic name Mac Eochaidh, or son of Eochaidh.

The meaning comes from the Irish word for a horse.


This is an Anglicized form of the Gaelic name Ó Catharnaigh, or descendant of Catharnach.

We’ve seen the Irish word cath earlier, which refers to a battle or war. The rest of the personal name brings the meaning of “warlike”. 


This is an Anglicized form of the Gaelic name Ó Céileachair, or descendant of Céileachar.

The word céile refers to a spouse or companion. The full name means “dear companion” or “dear spouse”.

Patrick Woulfe, a scholar in the early 20th century, states that an early family of the name in Munster were descended from a brother of Brian Boru, the great High King of Ireland.


Keating is interesting because it ultimately derives from an Anglo-Norman name that arrived into Ireland with the Norman Invasion.

After William the Conqueror led the Norman Conquest of Britain, the Anglo-Normans spread to Ireland from 1169.

The Norman name we’re talking about here was de Ketyng. The settlers eventually took a Gaelicized form of the name, Céitinn. In other words, that name sounds similar to the original but also sounds more naturally Gaelic.

Then later, families anglicized Céitinn into the similar-sounding English name of Keating.

A double hop, so to speak.  

Norman Knight


This is an Anglicized form of the Gaelic name Cinnsealach.

The meaning is something like “proud warrior”.


This is an Anglicized form of the Gaelic name Ó Céirín, or descendant of Céirín.

The word ciar refers to a dark black color, and the second syllable is a diminutive. So, it refers to the small dark-haired person.

More About The Anglicization Of Irish Surnames

You’ll find it easier to understand how Irish families changed their names with a bit more background.

The use of surnames in Ireland dates back to the tenth century. Children adopted the first name of their father and prefixed it with “Mac” or “O”, which means “son” and “descendent of”.

These names were in the Gaelic language.

In later centuries when Ireland was under British rule, the use of the Gaelic language was curbed.

This led to the Irish making their names look and sound more English i.e. Anglicization.

The simplest way was to drop the O and Mac in front of a name.

Another way was to pick the nearest sounding English name.

The third way was to pick an English name that has the same meaning as the Gaelic name. The two names may sound completely different.

Other Irish Last Names From 1923 To 1932

We’ve covered the meanings and origins of the most common names in Ireland through the 1920s.

Here are the other names starting with K with at least thirty births in Ireland between 1923 and 1932.

Remember that many of these names were brought to America from different regions where they had different meanings.

From three hundred to eight hundred births

Last NameIrish Births 1923-322010 Census

From one hundred to three hundred births

Last NameIrish Births 1923-322010 Census

Over thirty births

Last NameIrish Births 1923-322010 Census

Index To Other Letters

Index To Other Letters

Looking for lists related to other letters? Check these out:

Index to Irish Last Names


Margaret created a family tree on a genealogy website in 2012. She purchased her first DNA kit in 2017. She created this website to share insights and how-to guides on DNA, genealogy, and family research.

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