The majority of Americans or their ancestors immigrated within the past five centuries, with the exception of the Native American population and people from Hawaii, Puerto Rico, Guam, and the Philippine Islands who became American through expansion of the country in the 19th century, and American Samoa, the U.S. Virgin Islands and Northern Mariana Islands in the 20th century.
Despite its multi-ethnic composition, the culture of the United States held in common by most Americans can also be referred to as mainstream American culture, a Western culture largely derived from the traditions of Northern and Western European colonists, settlers, and immigrants. It also includes influences of African-American culture. Westward expansion integrated the Creoles and Cajuns of Louisiana and the Hispanos of the Southwest and brought close contact with the culture of Mexico. Large-scale immigration in the late 19th and early 20th centuries from Southern and Eastern Europe introduced a variety of elements. Immigration from Asia, Africa, and Latin America has also had impact. A cultural melting pot, or pluralistic salad bowl, describes the way in which generations of Americans have celebrated and exchanged distinctive cultural characteristics.
In addition to the United States, Americans and people of American descent can be found internationally. As many as seven million Americans are estimated to be living abroad, and make up the American diaspora.
