What is the N-400: US Naturalization


Most US citizens are what are known as “natural born” citizens, either because they were born in the United States (jus soli) or its territories, or because they were born abroad to parent(s) who are citizens (jus sanguinis). Others become citizens through the process of naturalization.

Broadly speaking, naturalization is the means by which documented immigrants become US citizens. A person can become a citizen through self-naturalization or through a process known as “derivation,” which involves the citizenship status of at least one of the person’s parents.

The basis for the naturalization process is set forth in the U.S. Constitution, and the power to enact laws governing naturalization lies with Congress. Early on, however, the power to naturalize immigrants was given to state courts. That duty is now handled by the U.S. Citizenship and Immigration Services agency.

Article 1 of the Constitution grants Congress the power “to establish a uniform Rule of Naturalization.” The Constitution also uses the words “natural born citizen” in defining who is eligible to serve as president. Courts have since interpreted this term to mean that persons born in the country automatically become citizens, while others must be naturalized.

The 14th Amendment, meanwhile, states that “all persons born or naturalized in the United States and subject to the jurisdiction thereof shall be citizens of the United States and of the State in which they reside.” This served to prevent states from imposing varying citizenship standards, especially those that denied citizenship to natural-born Americans on the basis of race (although race remained a major barrier to citizenship for immigrants until after World War II).

Today hundreds of thousands of immigrants are naturalized each year in the United States. In 2011 more than 600,000 took the oath to become citizens. To become a U.S. citizen, an immigrant must meet certain criteria:

  • She must be at least 18 years old.
  • She be a lawful permanent resident with a green card for the five years before applying for citizenship. She must reside in the country for at least half of the five years and she must not leave the country for more than one year at a time.
  • She must live in the same state or district for at least three months.
  • She must be a “person of good moral character.” A history of aggravated felonies, drug crimes, gambling offenses, prostitution and some other criminal activities usually lead to disqualification.
  • She must pass an English literacy test and a test on U.S. history and government.
  • She must demonstrate “attachment” to the principles of the Constitution.
  • Finally, she must swear the oath of citizenship.

Slightly different rules apply to permanent residents who are married to citizens, those who have served in the military, and those who belong to a small group of other eligible applicants. This group includes so-called “U.S. nationals,” people who live in America’s outlying territories, such as American Samoa. These people are granted special status as Americans but are not citizens, meaning they have almost all the rights of citizenship but not the right to vote.


For these special categories, only three years of permanent residency are required. An immigrant who is married to U.S. citizens must have obtained permanent-resident status on the basis of the marriage and must have been married to the citizen for at least three years at the time of the application.

An alternate path to citizenship through naturalization is known as “derivation” or derivative citizenship. This happens when the actions of a parent or grandparent lead to a foreign-born child becoming a citizen. Previously, this meant only that if one or both parents became naturalized citizens, the child did as well. Now, however, that factor is combined with several others, including the child’s residency status.

Naturalization is a long, difficult process, and it’s only available to documented immigrants. But it provides a path to citizenship for millions of people striving to take part in the American dream. Most Americans take their “natural born” citizenship for granted, but to anyone who’s been through naturalization, it’s a hard-won prize.

