Immigraton Laws The first immigrants to the territory now the United States were from Western Europe. The first great migration began early in the 19th century when large numbers of Europeans left their homelands to escape the economic hardships resulting from the transformation of industry by the factory system and the simultaneous shift from small-scale to large-scale farming. At the same time, conflict, political oppression, and religious persecution caused a great many Europeans to seek freedom and security in the U.S. The century following 1820 may be divided into three periods of immigration to the U.S. During the first period, from 1820 to 1860, most of t