Home > West's Encyclopedia of American Law > Aliens

Foreign-born persons who have not been naturalized to become U.S. citizens under federal law and the Constitution.

The federal immigration laws determine whether a person is an alien. Generally, a person born in a foreign country is an alien, but a child born in a foreign nation to parents who are U.S. citizens is a U.S. citizen. The term alien also refers to a native-born U.S. citizen who has relinquished U.S. citizenship by living and acquiring citizenship in another country. Aliens are categorized in several ways: resident and nonresident, immigrant and nonimmigrant, documented and undocumented ("illegal").

Overview

The United States welcomes a large number of aliens every year. Millions of foreign-born persons travel, work, and study in the country, and hundreds of thousands more choose to immigrate and become U.S. citizens. All of them are subject to federal immigration law. At the simplest level, the law...