Ireland vs South Carolina: The Ups and Downs of Ireland’s Population

Céad Míle Fáilte, and welcome to your Letter from Ireland for this week. Well, January is living up to its reputation here in County Cork with low grey skies, persistent drizzle, and fields so waterlogged that the farmers look thoroughly fed up with the whole affair. Still, there’s something quietly comforting about a proper Irish winter. It reminds us why we value a good fire and a strong cup of tea. I’m firmly in the Barry’s tea camp today – hot and bracing. How are things in your part of the world?

As I sit here looking out across the mist-softened hills, I’ve been turning over a question that came up during a conversation with a reader from Charleston in South Carolina, USA last week. She remarked on how “empty” a lot of Ireland feels compared to home. It’s an observation visitors often make, and it opens the door to a much bigger story.

So. I hope you’ll join me now with a cup of whatever you fancy as we start into today’s letter.

Why Can Ireland Feel So Empty?

At first glance, the comparison between my reader’s home state of South Carolina and Ireland is striking. The island of Ireland (all 32 counties, North and South) covers just over 32,000 square miles, almost identical in size to the state of South Carolina.

Today, South Carolina has a population of a little over 5.3 million while the island of Ireland has around 7 million people. So while the area is the same, the population are not identical. But here’s the deeper puzzle.

South Carolina is one state among fifty, and part of a continent whose population has expanded rapidly over hundreds of years. By comparison, Ireland is an entire island with thousands of years of continuous human settlement, landscapes dense with ancient monuments, and most notably, a global diaspora of 70–80 million people who claim Irish ancestry.

Given all that history, why can Ireland still feel so sparsely populated? To answer that, we need to travel a long way back.

From Ice Age to Iron Age: Ireland’s Early Population

At the time the last Ice Age loosened its grip around 10,000 BC, Ireland was empty of humans. At that point, rising sea levels had already separated it from Britain, so when the first people arrived around 8000 BC, they came by boat and not over land bridges.

These early hunter-gatherers lived lightly on the land, and their numbers were tiny, perhaps only a few thousand people spread across the entire island.

But everything changed around 4000 BC with the arrival of farming. Crops and domesticated animals allowed communities to settle, food supplies to stabilise, and populations to grow. These were the people who farmed areas like the Céide Fields in County Mayo and built monuments such as Newgrange, a structure that still astonishes us today.

Moving on. By the Bronze Age (around 2000 BC), Ireland may have supported 100,000–200,000 people. By the early centuries AD, the population is usually estimated at somewhere between 300,000 and 500,000, dispersed across small kingdoms and rural landscapes. This is the Ireland we know from tales of the Heroes and myths.

Medieval Growth – and Repeated Shocks

The early medieval period brought steady growth. Monasteries became centres of learning, agriculture, and trade. By around 1000 AD, Ireland’s population may have reached 700,000 to 1 million.

Despite Viking raids, Norman invasion, and recurring conflict, the long-term population trend remained upward. On the eve of the Plantation period, around 1600, Ireland most likely had about 1.4 million people.

Fast forward to the 17th century, a time of devastation. War, famine, and disease, particularly during the 1640s and 1650s, may have reduced the population by as much as 20%. Recovery followed, and by 1700 Ireland was home to roughly 2 million people.

The 18th Century Population Explosion

Then came one of the most dramatic population surges in Irish history. Between 1700 and 1800, the population doubled, from 2 million to over 4 million.

The main reason was the potato – the simple spud! Introduced in the late 16th century, this hardy South American crop could thrive in poor soil and produce astonishing yields. A small plot could feed a large family. As a result, land could be subdivided again and again among large families. Rural populations expanded rapidly, particularly to the west and south.

The coming of the potato to this island and other social factors kept the population numbers climbing:

• 1821: 6.8 million people on the island
• 1841: 8.2 million people on the island

Ireland was more crowded than it had ever been with millions living on the narrow edge of subsistence, and dependent on a single crop. They mostly crowded into parts of the country that we recognise as empty today to the south and west of the island.

An Gorta Mór: The Great Breaking Point

When potato blight struck across Europe in 1845, it exposed how fragile that system had become. The crop failed again in 1846 and 1847. What followed became known as “An Gorta Mór” or “The Great Hunger”.

Between 1845 and 1852, about one million people died from starvation and disease, while another 1.5 to 2 million emigrated, many never to return. The 1851 census records a population of 6.6 million, down from 8.2 million ten years earlier. Remember, that census may not have been the most accurate given the fact it was recorded at the tail end of the famine.

But the most profound change came after the famine. The land subdivision that I mentioned earlier had largely ended. Farms were consolidated and passed intact to a single heir. The rest of the family left. Emigration became not a crisis response, but a real choice and eventually a way of life.

A Century of Departure

The population decline continued for generations:

• 1901: About 4.5 million on the entire island
• 1961: Just 2.8 million in the Republic of Ireland (26 counties to the south)

Another poignant sample reference is that the entire population of County Mayo was in continual decline from 1845 all the way to 1971. Ireland lost roughly two-thirds of its peak population, and the outward flow continued well into the late 20th century.

Only from the 1960s onward did the numbers start to stabilise. European Economic Community membership, industrialisation, and later the Celtic Tiger years finally slowed – and then reversed – the long decline.

Even today, with about 7 million people on the island, Ireland has still not returned to its 1841 population level.

What the Landscape Is Telling Us

So when visitors say Ireland feels “empty,” they’re not wrong. Places often look like they were once populated but somehow emptied of people. Those abandoned cottages, long-silent townlands, and quiet valleys are the physical traces of a vast demographic collapse. When your family research shows siblings scattered across America, Britain, Australia, and beyond, you’re seeing the human version of the same story.

Which brings us back to South Carolina. Similar in size, not hugely different in population, but formed by opposite historical forces. South Carolina’s story is one of accumulation. Ireland’s, for more than a century, was one of dispersal. The Irish diaspora is not just a cultural phenomenon, but a population that might have lived here, had history unfolded differently.

Understanding these numbers might help explain why return visits to Ireland are so emotionally charged, and why genealogy can matter so deeply to many of us. It reconnects families separated not by choice alone, but by necessity.

Ireland today is growing again: confident, creative, outward-looking and welcoming of visitors. But it still carries the memory of that great emptying in its quiet places. Wherever we are in the world, we carry that history in our family trees.

Have you ever thought about Ireland’s population in these terms? I’d love to hear your thoughts in the comments section below.

That’s it for this week.

Slán for now,
Mike.