20 Countries with the Highest Population of Irish Ancestry

Irish descendants are spread across Europe, with recent estimates indicating a staggering 80 million people. According to a report by Ireland’s Department of Foreign Affairs and Trade, half of this population live in North America.  

Although Irish men started to migrate in the early medieval periods, it was during the forced population transfers (1500 – 1800) and the Irish famine (1845-1842) that neighboring territories and continents experienced an influx.  

Today, the number of people with Irish ancestry varies between countries, with some recording a decrease, rapid increase, or stagnation. Below, we highlight the top 20 countries with the highest population of people with some Irish background.

Read – 10 Ways to Find Your Irish Ancestry

What Country Has The Most Irish Ancestry? 

The United States has the highest population of people with Irish ancestry. The 2021 Census Bureau recorded over 36 million people claiming to have Irish roots. This is over 10% of the 333 million US population count of 2024, five times more than the current population on the island of Ireland itself.  

However, according to a DNA-based study, the UK has the most Irish ancestry, probably because the average UK citizen has over 20% Irish inheritance. Given that people from Ireland, Britain, or Scotland tend to be genetically similar, researchers sought to trace the ethnic make-up of people as far back as 500 years.  

In this case, the study concluded that only a professional genealogist can help explore genetic clusters within countries, spot distinct regional differences, and break down the Irish inheritance in many UK nationals.  

Considering all these factors, here’s a list of the top 20 countries with the most people of Irish heritage.  

Countries with the Highest Population of Irish Ancestry 

1. The US 

According to the Census Bureau, people of Irish ancestry make up about 10% of the US population and counting. There are over 36 million Irish descendants in the US and over 150,000 Irish citizens.  

2. The UK 

Great Britain also boasts a whopping 6 million people with Irish heritage, including over half a million Irish-born citizens. This represents about 10% of the UK population and has steadily increased over the years.  

3. Canada 

The number of Irish diaspora in Canada is slightly over 4.5 million people, amounting to about 11.2% of the Canadian population and representing one of the highest percentages in a single country. Over 40,000 of these people are Irish citizens.  

4. Australia 

Irish are the third largest ethnic group in Australia, behind English and Australians, and represent 9% of the entire population. Ireland and Australia have a history from the First Fleet, as reflected by the ancestry numbers and the over 200,000 Irish citizens residing there.  

5. Spain 

Spain and Ireland enjoy close historical bonds stretching back to prehistoric times, so, unsurprisingly, 1.4 million people in Spain trace their lineage to Ireland. Currently, over 20,000 Irish citizens reside in Spain, making up a sub-total of 3% of the entire Spanish population.  

6. Germany 

1.2% of the German population comprises people with Irish heritage, numbering slightly more than 1 million. This includes over 15,000 Irish nationals living across Germany as students, workers, and businessmen.  

7. India 

With 1.4 billion people, India is the most populous nation. So, the 1 million people with an Irish background represent only about 0.1% of the total population. Anglo-Indians settled in India after the anti-imperialist rhetoric of Young Ireland.  

8. China 

It’s expected that due to the historical ties between China and Ireland and the Irish hype in China, the number of Irish descendants would be substantial in the second most populous country. On the contrary, about 8,000 Irish nationals are in China, and about 1 million people have Irish ancestry.  

9. France 

France’s population is 68 million, with slightly less than a million claiming Irish ancestry, including over 10,000 Irish nationals. However, the numbers have significantly faded recently, with more Irish communities migrating further west.  

10. New Zealand 

In the recent past, New Zealand also had close to a million people tracing their lineage back to Ireland, but the numbers have plummeted to about 450,000, including about 9,000 Irish citizens. These Irish descendants make up about 9% of the entire population.  

11. Argentina 

Like most South American nations, Argentina has descendants of families of soldiers, commonly referred to as the Wild Geese, who fought with the Spaniards. Today, about 1.2% (500,000) of Argentinians trace their ancestry to Ireland.  

12. Poland 

Poland currently hosts about 8,000 Irish citizens, making up over 500,000 of its population with Irish ancestry. Poland, which is to the west of the island of Ireland, reported a total population of 36.8 million in the 2022 census.  

13. Mexico 

Despite the correlation between Spaniards, Mexicans, and Irish genetics, the number of people reporting Irish ancestry in Mexico has drastically continued to decrease, with the most recent available estimates putting the figure at below 200,000 of the 127.8 million people.  

14. The Caribbean 

The Caribbean was one of the favorite destinations for Irish nationals, as depicted by the dominance in Montserrat, which remains an Irish ancestry powerhouse. However, the 44 million population is scattered across the Islands of Jamaica, Puerto Rico, Barbados, and more. As a result, the number of Irish descendants has drastically decreased to a few hundred thousand.  

15. Uruguay 

Only 3.6% of the Oriental Republic of Uruguay’s 3.5 million people claim an Irish background. This translates to about 250,000 people, including about 2,000 nationals, a drastic decrease from what has been witnessed historically.  

16. UAE 

The United Arab Emirates has been a favorite destination for most Irish nationals seeking to join the educational, business, healthcare, and hospitality sectors. The country recorded over 20,000 Irish citizens and over 100,000 British nationals in 2023. About 200,000 of these are believed to have Irish heritage.  

17. Chile 

Chile received some of its first Irish immigrants as soldiers in the 1500s. More arrivals have been witnessed over the centuries, boosting the number of nationals with Irish backgrounds. However, today, only about 120,000 of these remain, including less than 400 Irish nationals.   

18. South Africa 

Slightly over 100,000 people in South Africa trace their ancestry to Ireland. Of these, about 1,000 are Irish-born. However, the number is dwindling and seen as a drop in the ocean for the over 62 million population.  

19. Brazil 

Despite being one of South Africa’s most populous states, Brazil has only about 80,000 nationals who can trace their roots to Ireland.  

20. Denmark 

According to the 2022 census, Denmark has a total population of 6 million. However, like many other countries beyond this point, there’s a meager number of people claiming Irish ancestry. Currently, around 2,400 Irish citizens live in Denmark, and about four times that number can trace their roots to Ireland.  

Check Your Genealogy 

If you’re in any of these countries, consider taking a DNA test or a comprehensive genealogy to determine your Irish alignment. A fraction of Irish heritage in your DNA results does not entirely mean that you qualify for Irish citizenship but could hint at your ancestry.  

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