text: irish immigrants? does anyone know what year the irish immigrants began going to america? thanks. great irish famine (1740-1741) due to unseasonble bad weather resulted in poor crops.    many scots irish protestants moved to america before 1776, settling especially in frontier areas of pennsylvania, virginia and the carolinas. much of the south also shows their historic imprint.  potato famine....fungal infection in the potato crop.....  during and after the irish potato famine (or great famine (an gorta mór)) of 1845-1849, millions of irish catholics came to north america. many arrived in canada on disease-ridden ships referred to as coffin ships. some of them remained there, especially in toronto and ontario, and became irish-canadians; others moved to the united states. between 1820 and 1860, one third of all immigrants to the united states were irish catholics, and in the 1840s, they comprised nearly half of all immigrants