To use Form N-400, the applicant must be ONE of the following:
- A Lawful Permanent Resident for at least five years and at least 18 years old;
- A Lawful Permanent Resident for at least three years and at least 18 years old, a. AND the applicant has been married to and living with the same U.S. citizen for the last three years,
- AND the applicant has been married to and living with the same U.S. citizen for the last three years,
- AND the applicant’s spouse has been a U.S. citizen for the last three years.
- A member of one of several other groups eligible to apply for naturalization (for example, persons who are nationals but not citizens of the United States) and at least 18 year sold.
- A person who has served honorably in the U.S. Armed Forces,
- AND If the applicant is at least 18 years old, a Lawful Permanent Resident with at least one year of U.S. Armed Forces service, and the applicant is filing his or her application for naturalization while still in the service or within six months after the termination of such service.
- OR the applicant served honorably as a member of the Selected Reserve of the Ready Reserve or in active-duty status during a designated period of hostilities. The applicant then may apply for naturalization without having been physically present in the United States for any specified period.