Why did the Irish immigrate to the United States during the 1840s and 1850s?

• England invaded Ireland during the mid-1840s, displacing the Irish population.
• They fled a famine caused by severe overpopulation and a devastating blight on the potato crop. 
• The expansion of the industrial revolution displaced Irish workers. 
• Anti-Catholic violence forced the Irish to flee their homeland.

ANSWER: They fled a famine caused by severe overpopulation and a devastating blight on the potato crop.