Irish immigrants began coming to America in large numbers in the 1840s due to the potato famine and resulting poverty in Ireland. They faced difficult conditions on overcrowded ships during the journey and often lived in poor quality shanty towns with little money or resources upon arrival. While they faced discrimination and stereotyping, Irish immigrants eventually established communities and found work in areas like canals, railroads, and factories. As more generations were born in America, assimilated and gained opportunities, the social and economic status of Irish immigrants and their descendants significantly improved by the late 1800s and early 1900s.