<Tr> <Th_colspan="4"> Total: 4,787,580 </Th> </Tr> <P> Irish immigration had greatly increased beginning in the 1820s due to the need for labor in canal building, lumbering, and civil construction works in the Northeast . The large Erie Canal project was one such example where Irishmen were many of the laborers . Small but tight communities developed in growing cities such as Philadelphia, Boston, New York and Providence . </P> <P> From 1820 to 1860, 1,956,557 Irish arrived, 75% of these after the Great Irish Famine (or The Great Hunger, Irish: An Gorta Mór) of 1845--1852, struck . </P> <P> Of the total Irish immigrants to the U.S. from 1820 to 1860, many died crossing the ocean due to disease and dismal conditions of what became known as coffin ships . </P>

The mass emigration of the irish in the mid-19th century was primarily a result of