The Great Famine, also known as the Great Hunger (Irish: an Gorta Mór [ənˠ ˈɡɔɾˠt̪ˠə ˈmˠo:ɾˠ]), the Famine and the Irish Potato Famine,[1][2] was a period of mass starvation and disease in Ireland lasting from 1845 to 1852 that constituted a historical social crisis and had a major impact on Irish society and history as a whole.[3] The most severely affected areas were in the western and southern parts of Ireland—where the Irish language was dominant—hence the period was contemporaneously known in Irish as an Drochshaol,[4] which literally translates to "the bad life" and loosely translates to "the hard times".

The worst year of the famine was 1847, which became known as "Black '47".[5][6] The population of Ireland on the eve of the famine was about 8.5 million; by 1901, it was just 4.4 million.[7] During the Great Hunger, roughly 1 million people died and more than 1 million more fled the country,[8] causing the country's population to fall by 20–25% between 1841 and 1871, with some towns' populations falling by as much as 67%.[9][10][11] Between 1845 and 1855, at least 2.1 million people left Ireland, primarily on packet ships but also on steamboats and barques—one of the greatest exoduses from a single island in history.[12][13]

The proximate cause of the famine was the infection of potato crops by blight (Phytophthora infestans)[14] throughout Europe during the 1840s. Impact on food supply by blight infection caused 100,000 deaths outside Ireland, and influenced much of the unrest that culminated in European Revolutions of 1848.[15] Longer-term reasons for the massive impact of this particular famine included the system of absentee landlordism[16][17] and single-crop dependence.[18][19] Initial limited but constructive government actions to alleviate famine distress were ended by a new Whig administration in London, which pursued a laissez-faire economic doctrine, but also because some in power believed in divine providence or that the Irish lacked moral character,[20][21] with aid only resuming to some degree later. Large amounts of food were exported from Ireland during the famine and the refusal of London to bar such exports, as had been done on previous occasions, was an immediate and continuing source of controversy, contributing to anti-British sentiment and the campaign for independence. Additionally, the famine indirectly resulted in tens of thousands of households being evicted, exacerbated by a provision forbidding access to workhouse aid while in possession of more than one-quarter acre of land.

The famine was a defining moment in the history of Ireland,[3] which was part of the United Kingdom of Great Britain and Ireland from 1801 to 1922. The famine and its effects permanently changed the island's demographic, political, and cultural landscape, producing an estimated 2 million refugees and spurring a century-long population decline.[22][23][24][25] For both the native Irish and those in the resulting diaspora, the famine entered folk memory.[26] The strained relations between many Irish people and the then ruling British government worsened further because of the famine, heightening ethnic and sectarian tensions and boosting nationalism and republicanism both in Ireland and among Irish emigrants around the world. English documentary maker John Percival said that the famine "became part of the long story of betrayal and exploitation which led to the growing movement in Ireland for independence." Scholar Kirby Miller makes the same point.[27][28] Debate exists regarding nomenclature for the event, whether to use the term "Famine", "Potato Famine" or "Great Hunger", the last of which some believe most accurately captures the complicated history of the period.[29]

The potato blight returned to Europe in 1879 but, by this time, the Land War (one of the largest agrarian movements to take place in 19th-century Europe) had begun in Ireland.[30] The movement, organized by the Land League, continued the political campaign for the Three Fs which was issued in 1850 by the Tenant Right League during the Great Famine. When the potato blight returned to Ireland in the 1879 famine, the League boycotted "notorious landlords" and its members physically blocked the evictions of farmers; the consequent reduction in homelessness and house demolition resulted in a drastic reduction in the number of deaths.[31]