The Great Irish Famine Was a Turning Point for Ireland and America

A pencil sketch of starving Irish people in the 1840s.

Internet Archive Book Images/Wikimedia Commons/Public Domain

In the early 1800s, the impoverished and rapidly-growing rural population of Ireland had become almost totally dependent on one crop. Only the potato could produce enough food to sustain families farming the tiny plots of land the Irish peasants had been forced onto by British landlords.

The lowly potato was an agricultural marvel, but staking the lives of an entire population on it was enormously risky.

Sporadic potato crop failures had plagued Ireland in the 1700s and early 1800s. In the mid-1840s, a blight caused by a fungus struck potato plants across all of Ireland.

The failure of essentially the entire potato crop for several years led to unprecedented disaster. Both Ireland and America would be changed forever.

The Irish Potato Famine

The Irish Potato Famine, which in Ireland became known as "The Great Hunger," was a turning point in Irish history. It changed Irish society forever, most strikingly by greatly reducing the population.

In 1841, Ireland's population was more than eight million. It has been estimated that at least one million died of starvation and disease in the late 1840s, and at least another one million immigrated during the famine.

Famine hardened resentment toward the British who ruled Ireland. Nationalist movements in Ireland, which had always ended in failure, would now have a powerful new component: sympathetic Irish immigrants living in America.

Scientific Causes

The botanical cause of the Great Famine was a virulent fungus (Phytophthora infestans), spread by the wind, that first appeared on the leaves of potato plants in September and October of 1845. The diseased plants withered with shocking speed. When the potatoes were dug up for harvest, they were found to be rotting.

Poor farmers discovered the potatoes they could normally store and use as provisions for six months had turned inedible.

Modern potato farmers spray plants to prevent blight. But in the 1840s, the blight was not well understood, and unfounded theories spread as rumors. Panic set in.

The failure of the potato harvest in 1845 was repeated the following year, and again in 1847.

Social Causes

In the early 1800s, a large part of the Irish population lived as impoverished tenant farmers, generally in debt to British landlords. The need to survive on small plots of rented land created the perilous situation where vast numbers of people depended on the potato crop for survival.

Historians have long noted that while Irish peasants were forced to subsist on potatoes, other crops were being grown in Ireland, and food was exported for market in England and elsewhere. Beef cattle raised in Ireland were also exported for English tables.

British Government Reaction

The response of the British government to the calamity in Ireland has long been a focus of controversy. Government relief efforts were launched, but they were largely ineffective. More modern commentators have noted that economic doctrine in 1840s Britain generally accepted that poor people were bound to suffer and government intervention was not warranted.

The issue of English culpability in the catastrophe in Ireland made headlines in the 1990s, during commemorations marking the 150th anniversary of the Great Famine. Britain's then-Prime Minister Tony Blair expressed regret over England's role during commemorations of the 150th anniversary of the famine. The "New York Times" reported at the time that "Mr. Blair stopped short of making a full apology on behalf of his country."


It is impossible to determine precise numbers of the dead from starvation and disease during the Potato Famine. Many victims were buried in mass graves, their names unrecorded.

It has been estimated that at least half a million Irish tenants were evicted during the famine years.

In some places, particularly in the west of Ireland, entire communities simply ceased to exist. The residents either died, were driven off the land, or chose to find a better life in America.

Leaving Ireland

Irish immigration to America proceeded at a modest pace in the decades before the Great Famine. It has been estimated that only 5,000 Irish immigrants per year arrived in the United States prior to 1830.

The Great Famine increased those numbers astronomically. Documented arrivals during the famine years are well over half a million. It is assumed that many more arrived undocumented, perhaps by landing first in Canada and walking into the United States.

By 1850, the population of New York City was said to be 26 percent Irish. An article titled "Ireland in America" in the "New York Times" on April 2, 1852, recounted the continuing arrivals:

On Sunday last three thousand emigrants arrived at this port. On Monday there were over two thousand. On Tuesday over five thousand arrived. On Wednesday the number was over two thousand. Thus in four days twelve thousand persons were landed for the first time upon American shores. A population greater than that of some of the largest and most flourishing villages of this State was thus added to the City of New York within ninety-six hours.

Irish in a New World

The flood of Irish into the United States had a profound effect, especially in urban centers where the Irish exerted political influence and got involved in municipal government, most notably in the police and fire departments. In the Civil War, entire regiments were composed of Irish troops, such as those of New York's famed Irish Brigade.

In 1858, the Irish community in New York City had demonstrated that it was in America to stay. Led by a politically powerful immigrant, Archbishop John Hughes, the Irish began building the largest church in New York City. They called it St. Patrick's Cathedral, and it would replace a modest cathedral, also named for Ireland's patron saint, in lower Manhattan. Construction was halted during the Civil War, but the enormous cathedral was finally finished in 1878.

Thirty years after the Great Famine, the twin spires of St. Patrick's dominated the skyline of New York City. And on the docks of lower Manhattan, the Irish kept arriving.


"Ireland in America." The New York TImes, April 2, 1852.

Lyall, Sarah. "Past as Prologue: Blair Faults Britain in Irish Potato Blight." The New York Times, June 3, 1997.

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McNamara, Robert. "The Great Irish Famine Was a Turning Point for Ireland and America." ThoughtCo, Aug. 28, 2020, McNamara, Robert. (2020, August 28). The Great Irish Famine Was a Turning Point for Ireland and America. Retrieved from McNamara, Robert. "The Great Irish Famine Was a Turning Point for Ireland and America." ThoughtCo. (accessed June 8, 2023).