How to Get US Citizenship as a Foreigner: Every Route Explained

For many people, US citizenship is the end goal: a passport, the vote, and the security of knowing no one can take your status away. But there's no application form for "citizenship as a foreigner". You get there through one of a handful of legal routes, and most of them take years.

This guide maps every route to US citizenship as of September 2026, so you can see which one might apply to you or your children. If you're already a green card holder and want the detailed rules on residence, the test and Form N-400, read our companion guide to US citizenship residency requirements.

The routes at a glance

Route 1: being born in the United States

The Fourteenth Amendment to the Constitution makes people born in the US, and subject to its jurisdiction, citizens at birth. This is often called birthright citizenship.

In January 2025, an executive order tried to deny citizenship to some US-born children whose parents were in the country unlawfully or temporarily. On 30 June 2026, in Trump v. Barbara, the Supreme Court held that children born in the US to parents unlawfully or temporarily present are subject to US jurisdiction and are citizens at birth.

So if your child is born in the US, they're generally a US citizen, whatever your own status. The long-standing exception is children of foreign diplomats with full immunity.

A US-born child can't sponsor parents for a green card until the child is 21. Having a baby in the US isn't a shortcut to immigration for the parents.

Route 2: born abroad to a US citizen parent

Citizenship can pass from parent to child even when the child is born outside the US. This is sometimes called acquisition of citizenship at birth. The rules depend on the date of birth and the parents' situation, and they're strict.

According to the USCIS Policy Manual, for a child born abroad on or after 14 November 1986 to married parents:

• Both parents are US citizens: at least one must have lived in the US at some point before the birth.
• One parent is a US citizen and the other isn't: the US citizen parent must have been physically present in the US for at least five years before the birth, with at least two of those years after age 14.

Different rules apply to children born to unmarried parents, and older rules apply to earlier births. If you think you might be a citizen through a parent, gather proof of their time in the US: school records, tax returns, employment records and old passports.

Parents usually document the child's citizenship by applying for a Consular Report of Birth Abroad at a US embassy, and a US passport. Adults who were never documented can apply for a Certificate of Citizenship on Form N-600.

Route 3: deriving citizenship as a child

Under section 320 of the Immigration and Nationality Act, a child born abroad can become a citizen automatically after birth if all of these are true at the same time, before the child turns 18:

• At least one parent is a US citizen, by birth or naturalization.
• The child is a lawful permanent resident, with a green card.
• The child lives in the US in the legal and physical custody of the US citizen parent.

This often happens when a parent naturalizes while their green-card-holding child still lives with them. The child doesn't take a test or an oath. The conditions can be met in any order, as long as they're all met together before the 18th birthday.

A child who lives abroad may be able to get citizenship through a different process, using Form N-600K, if the US citizen parent or grandparent meets physical presence rules.

Route 4: naturalization for adults

Most foreign-born adults become citizens through naturalization. It has two stages: first a green card, then citizenship.

Stage one: become a permanent resident

You need a green card through family, employment, the Diversity Visa lottery, refugee or asylum status, or another category. Our guide to different ways to migrate to the USA compares them, and our EB visa ranking covers the employment routes.

Stage two: naturalize

USCIS lists these core requirements for the standard five-year route:

• Be at least 18 when you file.
• Have five years of continuous residence as a green card holder.
• Be physically present in the US for at least 30 months of those five years.
• Live for at least three months in the state or USCIS district where you apply.
• Show good moral character.
• Pass tests in English and in US history and government (civics).
• Show attachment to the principles of the Constitution and take the Oath of Allegiance.

If you're married to and living with a US citizen, the residence period is three years, with 18 months of physical presence. Certain members of the US armed forces can naturalize under special rules, sometimes without any residence period.

Costs to plan for

These USCIS fees come from the fee schedule dated 9 September 2026. A fee waiver is available for some applicants on Form I-912. The State Department sets separate fees for passports and Consular Reports of Birth Abroad, so check its website.

The bigger costs often come earlier, on the road to a green card: immigration fees, medical exams, legal help and the cost of moving. Once you're in the US, plan for health insurance, a rental deposit and building a credit history from scratch.

What citizenship gives you, and what it asks

Citizenship brings the right to vote in federal elections, a US passport, protection from deportation, eligibility for federal jobs that require citizenship, and faster family sponsorship. Citizens can petition for spouses, children, parents and siblings, and some of those categories have no annual limit.

In return, you swear allegiance to the US and accept obligations such as jury service. US citizens are taxed on their worldwide income, even when they live abroad. And once you're a citizen, you must use a US passport to enter and leave the US.

The US doesn't require you to give up your other nationality, but your home country may not allow dual citizenship. Check its rules before you take the oath.

Your path, step by step

1. Check whether you're already a citizen. If a parent was a US citizen when you were born, look into acquisition before anything else.
2. Check your children's status. A child may have derived citizenship automatically when you naturalized.
3. If you're not a permanent resident, identify the green card route that fits you.
4. Once you have a green card, track your continuous residence and physical presence from day one.
5. File Form N-400 when you're eligible. USCIS allows filing up to 90 days before you reach the required residence period.
6. Prepare for the interview and tests, then attend your oath ceremony.

Scams and myths

• "Buy US citizenship" offers. There's no such thing. Investment routes lead to a green card at most.
• Consultants promising a fast-tracked N-400. USCIS decides, and no one can buy priority.
• Fake "notarios". In many countries a notary is a lawyer, but in the US a notary public can't give immigration advice. Use a licensed attorney or an accredited representative.
• Claiming to be a US citizen when you're not, including on job forms or voter registration. A false claim can lead to permanent bars.

Your checklist

• Work out which route applies to you and each family member.
• Collect proof of any US citizen parent's time in the US.
• If you're a green card holder, log every trip abroad.
• Budget for USCIS fees, and check whether you qualify for a reduced fee.
• Check your home country's rules on dual citizenship.
• Get legal advice if you have any arrest, long absence or past immigration problem.

US citizenship is achievable for many people, but rarely quickly. Knowing which route you're on is the first step to getting there without costly mistakes.