The Devastating Irish Potato Famine (Causes + Effects)

Causes effects Irish Potato Famine

The Irish Potato Famine, or the “Great Famine” as historians call it, was a terribly deadly event in the mid 19th century. It was one of the last major famines in Western European history and perhaps most surprisingly happened next door to the world’s dominant power of the time.

The famine was brought upon by a potato blight that ravaged Ireland’s potato crop for multiple years over a five year period. Ireland was primarily an agricultural nation and the potato was its linchpin and dominant crop.

The potato was introduced to Ireland nearly 100 years prior to the 1845 famine, yet it quickly gained favor. Its ability to grow well in poor soil, provide a higher caloric value than grain, and relative inexpensiveness were primary factors behind its rise.

The potato famine proved disastrous, particularly to the rural poor who overwhelmingly relied upon the crop. Mass death from starvation and disease followed, as well as emigration by those looking to escape the horrors.

The British government’s (who governed Ireland at the time) response to the famine did little to provide relief and arguably made the suffering worse. Historians debate today whether the lack of an effective response was ineptitude or out of malice towards the Irish.

The aftermath of the Irish potato famine led to dramatic changes to Ireland’s social, economic, and political institutions as well as demographics and population. The Great Famine had far-reaching impacts not only in Ireland, but across the globe.

When Was the Irish Potato Famine?

The Irish potato famine first began in 1845 and lasted until around 1850. Famine was not a new occurrence in Ireland as the population experienced several in the century prior. The Great Famine separated itself from the others given the enormity and drastic aftereffects. 

A potato blight caused the famine, more specifically a strain of fungus called phytophthora infestans that arrived in Ireland in 1845. The fungus infected potato plants through their leaves and left behind shriveled, inedible tubers.

The first year it arrived in 1845, nearly one-third of the crop was destroyed. The next year the blight was even worse, destroying anywhere from 75-90% of the potato crop. While the blight was absent in 1847, farmers largely did not plant potatoes that year in fear of destroyed crops.

Potato blight
Picture of potato blight via

Of course, the blight returned in 1848, yet again wreaking devastation on the new potato crops planted. The blight returned in 1849 and 1850, though to a lesser degree with some counties hit worse than others.

The poorest of the Irish were disproportionately affected by the potato failure. Many of these people were subsistence tenant farmers that grew only enough to feed themselves and pay the rent on their land. When the potato crop failed, starvation ensued beginning in 1846, though the worst of it was between 1847-1848.

During the early years of the famine, riots and protests erupted demanding aid and assistance. Eventually these subsided as despair and desperation set in. As people congregated together, disease from weakened immune systems spread rampant through the population.

Nearly one-million people, or one-eighth of the Irish population, would go on to die during the famine.

Causes of the Irish Potato Famine

While the primary cause of the Irish potato famine was the potato blight, there were many reasons as to why so many people died in the crisis. Two other causes of the Irish potato famine included the structure of the Irish economy, as well as the inept British response.

Most Irish land was owned by the Anglo-Irish or Protestant minority that had close ties to Britain. A large number of the landowners did not even live in Ireland but had stewards manage the lands for them.

The lands were often worked by the poorest Irish, many of whom were subsistence tenant farmers. The Irish divided and subdivided their land to the point where 25% of all holdings were between 1-5 acres and 40% between 5-15 acres. When the potato crop failed, there was neither food to eat nor any money to pay the rent. 

This led to mass evictions where the poorest had no food to eat and no place to live. One such landlord by the name of Major Dennis Mahon used the famine as an opportunity to clear over 1,500 families off his land during the height of the crisis. In all, over 70,000 evictions took place, displacing nearly 500,000 people.

Irish Potato Famine depiction
Depiction of Irish families begging for food via Wikimedia

The inept British government response arguably worsened the famine. Initially the decisive British actions held off the worst of the famine. Parliament repealed the “Corn Laws” making corn and bread less expensive, and organized the distribution of vast quantities of food, chiefly “Indian meal.

Following a British administration change, the new Whigs in charge took more of a laissez-faire approach to the famine. The Whigs were adamant that the Irish continued their exports of grain and cattle, despite the thousands of people dying every day.

While the British organized soup kitchens to help feed the starving population, Parliament ended those in August 1847 citing their fear that the poor would become too dependent on the government.

The British also adopted a policy of letting the Irish pay for their own famine in mid-1847, including making landlords responsible for contributing to relief. The issue was that most Irish landlords were not Irish, and as such used a loophole called the “Gregory Clause” to avoid paying any relief at all.1

The lack of an effective British response to the famine no doubt contributed to the enormity of the crisis and surely increased the death count from what it could have been.

Effects of the Irish Potato Famine

Three primary effects of the Irish potato famine included a dramatic population decrease in Ireland, various economic and demographic shifts, and mass societal changes such as a near death blow for the Irish language.

When the Great Famine finally subsided in 1850-1851, Irish society was profoundly altered. In addition to the roughly one million dead, another 1.5 million or so emigrated and fled the destitute conditions.

Dramatic Population Decrease

As a result of the Great Famine, Ireland experienced a massive population loss. Roughly one million people died as a result of the famine, and nearly 1.5 million people emigrated in its aftermath.

The mass exodus of the Irish population did not stop there. From a high of ~8.2 million people in 18412, the population decreased to 6.88 million in 1850, down to 4.47 million in 1900 and even further to 4.18 million in 1930.

Irish immigration 1840s
Irish population decline in 1840s via Wikimedia

1930 proved to be a low point, with the population slowly rising from there. Even so, Ireland’s population has still not come close in modern times to the highs it experienced in the 1840s.

After the famine ran its course, Ireland continued to see mass emigration. Historians estimate that between 1851 and 1900 about 4.18 million people emigrated out of Ireland.

The massive population loss was a huge blow to Ireland, and drastically changed the societies of America, Canada, and Australia, among others. The new Irish immigrants helped these places to expand and grow, though tensions arose from the majority Catholic immigrants intermingling with the existing Protestant communities.

Economic and Demographic Shifts

Perhaps one of the biggest changes from the famine was the gradual decoupling of the Irish economy to the potato. The famine showed how the overreliance on one crop could lead to disastrous effects and Irish agriculture adapted accordingly.

The share of the potato among total crops declined from 55.5% prior to the famine, to just 12.5% in 1900.3

In general, the Irish economy shifted away from primarily producing agriculture. Many landowners sought to increase profits and encouraged converting their lands to pastures to raise livestock for export.

The Irish Potato Famine Effects on Agriculture statistics

In addition, existing farms grew larger in size after the famine. Irish families began to shift away from subdividing lands among many children. Small farm sizes likely worsened the famine by making too many families dependent on their small farms for food.

While the famine drastically lowered the overall population of Ireland, not all areas suffered population loss. In fact, Ireland’s three largest cities, Dublin, Belfast, and Cork actually saw their populations increase due the famine’s lessened effects in the cities and the massive influx of rural poor flocking to the cities in search of food, work, and aid.

The trend has flowed to the modern day as cities continue to see their populations rise, while more rural areas declined or stagnated.

Societal Changes

In the period after the famine, Irish society also faced some big changes. Pre-famine, most Irish people married young and had large family sizes. Post-famine, people married much later, or not at all if they did not have steady employment or land. In turn, these factors lowered the overall birth rates in Ireland which further exacerbated the population decline.

The famine would also prove to be a near death blow for the Irish language. While the number of Irish speakers was already in decline prior to the famine, in 1845 nearly 30% of the population still spoke it.

A vast majority of the people who died in the famine or emigrated following the famine were Irish speakers. The population decline and further emigration meant that by 1926 only 18% of the population still spoke Irish.4

Irish Potato Famine landlord
Depiction of a land seizure in Ireland via LOC

The modern Irish nation has prioritized the learning of the Irish language and helped revive it from the depths. Despite a higher level of Irish language proficiency among the population, only about 3% of the population is fluent.

Another major societal change was in religion. Ireland has always been a religious society, though evidence shows that in the aftermath of the famine, church attendance largely increased. The Irish Catholic clergy gained power over life and society and Irish Catholics became known for their strict adherence to their religion.

Finally, the famine produced high levels of anti-British sentiment. The inept British response led many Irish to believe their acts were intentional and it strengthened their resolve for an independent Irish nation.

The famine was one of the factors that led to the emergence of the violent Irish national organizations such as the Fenians and the Irish Republican Army. Eventually, Ireland would gain its independence from Britain in 1922.


1) Walker, Brian M. “Villain, Victim or Prophet?: William Gregory and the Great Famine.” Irish Historical Studies, vol. 38, no. 152, 2013, pp. 579–99. JSTOR,

2) Carney, F. J. “Pre-Famine Irish Population: The Evidence from the Trinity College Estates.” Irish Economic and Social History, vol. 2, 1975, pp. 35–45. JSTOR,

3) O’Rourke, Kevin. “The Economic Impact of the Famine in the Short and Long Run.” The American Economic Review, vol. 84, no. 2, 1994, pp. 309–13. JSTOR,

4) Ó Gráda, Cormac; “The Great Irish Famine“, Cambridge University Press, 1989

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