Naturalization is the process by which US citizenship is granted to a foreign national if he/she meets the requirements established by the Immigration and National Act (INA).
In most cases, an applicant for naturalization must be a permanent resident (green card holder) before starting the procedure.
Except in the case of certain members of the US Armed Forces and their dependents, naturalization can only be granted in the United States.
You may be eligible for naturalization if:
- You have been a permanent resident for at least five years and meet all other eligibility requirements.
- You have been a permanent resident for 3 years, and meet all eligibility requirements necessary to process naturalization as a spouse of a US citizen.
- You have provided eligible service in the US Armed Forces and meet all other eligibility requirements.
- Your child may be eligible for naturalization if you are a US citizen, the child was born outside the US and the child now lives outside the US, and all other eligibility requirements are met.
See the link for more information on these requirements: http://www.uscis.gov/policymanual/HTML/PolicyManual-Volume12-PartD.html