What were the four eras of immigration

1607-1830 the first Colonial settlements in Jamestown and Plymouth,

1830-1880 were primarily Irish and German to the United states,

1890-1920 the foreign-born had swollen to 15% of the US population,

and 1900 - 1970 the USA in the middle of the 20th century growing businesses had to look inside America for new sources of labor.