Who Can Apply for Naturalization
Based on the Immigration and Nationality Act's standing eligibility rules, last checked August 26, 2026.
Before Form N-400, USCIS, the civics test, or any of it — there are a handful of underlying rules that decide whether you’re eligible to apply at all. Here they are, in plain language.
The standard 5-year rule
Most applicants qualify by having been a lawful permanent resident (green card holder) for at least 5 years immediately before filing Form N-400, with no single trip abroad of a year or more during that period.
The 3-year rule (married to a U.S. citizen)
If you've been a permanent resident for at least 3 years and have been married to, and living with, the same U.S. citizen spouse for those 3 years, you can file after 3 years instead of 5. Your spouse must have been a citizen for that entire period too.
Continuous residence
You must have maintained the U.S. as your main home throughout the required period. A single trip of 6 months to a year outside the U.S. can raise a rebuttable presumption that you broke continuous residence; a trip of a year or more generally does break it, resetting the clock.
Physical presence
Separately from continuous residence, you must have actually been physically present in the U.S. for at least half of the required period — 30 months out of the 5 years, or 18 months out of the 3 years under the marriage rule.
Age and residence at filing
You must be at least 18 years old when you file, and have lived for at least 3 months in the state or USCIS district where you're applying before filing.
Good moral character
USCIS reviews your conduct during the statutory period (5 or 3 years) and generally beyond, checking for certain disqualifying convictions, failure to pay taxes or child support, and other conduct issues. This is assessed case by case, not a fixed checklist.
This is general information, not legal advice — eligibility rules have real exceptions (military service, certain past removal proceedings, disability waivers) that a general page like this can’t evaluate for your specific case. If anything here is unclear for your situation, talk to an immigration attorney or use USCIS’s own eligibility tool. Official source: USCIS’s N-400 page.