A broad overview of immigration to America

Perhaps a million immigrants came to America between 1565 and 1800, about 20 million in the nineteenth century, and at least 55 million in the twentieth century. During the twentieth century, particularly after World War II, as American immigration laws and regulations became more complex, the phenomenon of illegal immigration became increasingly significant. The numbers above include some 10 million illegal twentieth-century immigrants.

Even these approximate numbers are, in a sense, illusory, as they seem to record a permanent move from one nation to another. Yet, from the earliest colonial times, many who came either returned or went somewhere else, and many of those came back again. Specialists estimate that perhaps one immigrant in three later left. Many of these, often called sojourners, always intended to return: but many who came as sojourners - usually to make money - actually stayed, while others, who came intending to remain, eventually left. Almost certainly the most reliable statistic about American immigration is the incidence of immigrants - that is persons who were born somewhere else - in the total population.