Immigration became a major factor in American life in the antebellum period, and the influence of the many cultures represented by the growing tide of newcomers changed American culture itself. During the period from the American Revolution through the Napoleonic Wars in Europe (1776–1815), immigration from Europe to America had fallen to low levels. This began to change in the period around 1820. Restrictions upon emigration from Europe were lessened with the end of the Napoleonic Wars; American expansion after the War of 1812, fought with Great Britain, promised land and jobs to the immigrants.

ECONOMIC AND SOCIAL CAUSES

The general forces driving immigration to the United States during the period 1820–1870 are seen in the interactions between social and economic conditions in Europe and those in the United States. Europe saw unprecedented population...