• The great Irish potato famine of the 19th century prompted mass emigration.potato image by Stephen Orsillo from Fotolia.com
  
  Millions of American and Canadian citizens can trace their ancestries to Ireland. Those who do find that their forebears had difficult lives, which impelled many of them to leave Ireland and go anywhere else they could. They fled poverty, unemployment and the worst human disaster in the country's history, the Great Famine.
  
  

Overpopulation

• In the late eighteenth century, Britain began a war with France that restricted Britain's ability to trade with the rest of Europe. As a result, Britain increased trade with Ireland, which stimulated the Irish economy. A consequence of this was a baby boom, as Ireland could now support a growing population.
  
  The growth did not last long, however, as Britain reached a truce with France in 1815, and was once again able to import goods from Europe. Ireland's economy, reliant on now heavily reduced trade with Britain, declined. Land became scarce for the many young adult baby-boomers, and poverty was rife.
  
  In 1827, a change in the law made it much more affordable for people to emigrate. That year, 20,000 Irish people took advantage and fled their homeland.
  
  

Unemployment

• The development of agricultural machinery meant fewer laborers were needed to work on farms. During the industrial revolution, trade restrictions prevented Ireland from exporting glass and linen. As a result, there were very few manufacturers of these materials, few factories and few jobs.
  
  Britain ultimately lifted the trade restrictions, but that also made British goods available in Ireland. These goods were a lot less expensive, and quickly flooded the Irish market. Irish industry collapsed. Those working in factories had to return to agriculture, in which there were few jobs left because of advancements in technology.
  
  By 1835, only one-third of the workers in Ireland had regular jobs. Many people were forced to emigrate to find work.
  
  

The Great Famine

• The famine was caused partly by Ireland's dependency primarily on one resource, the potato. For many, it was their only source of food, and it was vital to the Irish economy through exportation. In 1845, a fungus blighted the potato crop and ruined the potato as a food staple.
  
  The next year, all of Ireland's potato crops were useless. The country also produced wheat on which it could survive, but the government exported it to Britain to raise money. One million Irish people died of starvation, and another 1.5 million emigrated.