The majority of modern-day Americans are of European ancestry. Of the remainder, most are of African descent; the descendants of Africans who were brought to these shores as slaves. Another large group is made up of Hispanics, those whose common language is Spanish and whose heritage is originally from Spain and Latin America.

The large number of immigrants in the late 1800s alarmed other Americans who accused them of working for less pay, thereby threatening others’ jobs. New laws were passed in 1882 to prevent immigrants with mental or physical problems that meant they might require public care. These laws also barred convicted criminals from entering the United States. Another law passed the same year was specifically aimed at the huge numbers of Chinese that had been pouring into America as a result of the Gold Rush. The Chinese Exclusion Act, which was extended in 1902, banned all immigration from China. It remained in effect until 1943, when China and the United States worked together during World War II.

People from many Asian countries have moved to America, especially since 1965, when a new system was established for determining how many people can emigrate each year from Asia to the United States. After the Vietnam War, immigrants from Cambodia, Laos, and Vietnam came in large numbers, escaping the terrible effects of war in their own countries. The largest group of current immigrants to America come from Mexico, Hispanic countries in Central and South America, and the Caribbean.

In addition to all the immigrants and descendants of immigrants, there are the numerous descendants of the various tribes of American Indians who populated this continent before it was settled by Europeans. They are now only a small percentage of the total population of the United States.