The Great Famine, also known as the Great Hunger (Irish: an Gorta Mór [ənˠ ˈɡɔɾˠt̪ˠə ˈmˠoːɾˠ]), the Famine and the Irish Potato Famine, 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. 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, 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". The population of Ireland on the eve of the famine was about 8.5 million; by 1901, it was just 4.4 million. During the Great Hunger, roughly one million people died and over one million more fled the country, causing the country's population to fall by 20–25% between 1841 and 1871, with some towns' populations falling by as much as 67%. 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.