What is the three countries that sent many immigrants to the US after civil war?

After the Civil War, many immigrants to the United States came from Ireland, Germany, and Italy. The Irish fled poverty and famine, particularly after the Great Famine in the 1840s. Germans sought political and economic opportunities, while Italians migrated in search of better prospects and to escape economic hardships in their homeland. These groups significantly contributed to the cultural and demographic landscape of the U.S. during that period.