This was a period of mass starvation and disease not only in Ireland but in many European countries, but Ireland, for many reasons, was worse. The Famine had a major impact of the Irish with the west and south most affected. More than a million people died and over 2 million left the country, many settling in the US.
The major cause was a potato blight that inflecting the potato crops. Other causes included single crop dependence (the potato), the continuous export of food from Ireland by London companies (Ireland was part of the United Kingdom), and absentee landlords, resulting in middle management exploiting tenants and resulting in evictions.
The potato came from South America and wasn’t popular at first. Landowners promoted the potato as a beneficial crop and by the latter half of the 17th century; it became a supplementary food source. Because the potato grew quickly in small spaces, it soon became by the 1800s a principal food.
Once the blight started, up to one half of the crops were destroyed by 1845 and most of the crop were lost by 1845.
This caused a major emigration from Ireland. Over one million went to North America and many went to England, Scotland, Australia, and other countries. If your ancestor left Ireland during the Potato Famine, there are many resources available. MyHeritage has an interesting blog on after the famine, so does FindMyPast. Both has Irish records as well as Ancestry and FamilySearch. The National Archives has a great blog on Irish children born at sea. Trace has information on emigration patterns and where to find records. The Library of Congress has guides to help point you in the right direction. Check out our blogs on Irish genealogy as well!
FamilyFinders