How to become a US citizen

The standard route requires being a lawful permanent resident for five years before filing. The clock starts from the date your permanent residence began, which appears on your green card, not from when you first entered the United States.

A shorter three-year period applies if you are married to and living with a US citizen. The requirement is stricter than it sounds: the marriage must be to the same US citizen spouse for the whole three years, that spouse must have been a citizen throughout, and you must be living in marital union at the time of filing and through to the oath. Separation before the oath can disqualify the application even at a late stage.

Members of the armed forces have separate provisions, in some cases with reduced or waived residence requirements, particularly for service during designated periods of hostilities.

You must be at least 18 to file for yourself. Children under 18 frequently acquire citizenship automatically when a parent naturalises, provided they are permanent residents living in that parent's legal and physical custody — a route that requires documenting the acquisition rather than applying for naturalisation.

You must have lived in the state or USCIS district where you file for at least three months before filing. This catches people who have recently moved, and it is a straightforward reason for rejection.

There are also applicants who are already US citizens and do not realise it. People born abroad to one or two US citizen parents may have acquired citizenship at birth, depending on the law in force at the time and their parents' residence history. If that might apply to you, resolving it is a different and generally simpler process than naturalising.

This is where well-prepared applications most often fail, because the two requirements measure different things and satisfying one does not satisfy the other.

Physical presence is arithmetic. You must have been physically inside the United States for at least half of the qualifying period — that is, at least 30 months out of the five years, or 18 months out of the three years. Every day outside the country counts against it, including short holidays. Applicants who travel frequently for work are the most likely to fall short without realising.

Continuous residence is a legal concept about whether you maintained the United States as your home. A single long absence can break it even if your total physical presence is comfortably sufficient. An absence of more than six months but less than a year creates a presumption that continuity was broken, which you can rebut with evidence. An absence of a year or more generally breaks it outright, and the clock restarts.

The evidence that rebuts a presumption is the evidence that you never left in a meaningful sense: you kept your home, kept employment, filed US tax returns as a resident, kept family in the United States, and did not take up employment abroad.

Filing a tax return as a non-resident, or claiming to be a non-resident for tax purposes, is treated as a serious indication that you abandoned residence. This is a common and avoidable trap.

If you need to be abroad for an extended period for a qualifying reason such as certain employment, a preservation of residence application exists — but it must be filed before you leave, not afterwards.

Work out both calculations carefully before filing. Reconstructing travel history is far easier with passport stamps, entry records and old boarding passes than from memory, and an application that fails on presence loses the fee and the time.

Good moral character is assessed over the qualifying period and, where relevant, beyond it. It is a legal standard rather than a general judgement, and specific conduct matters: certain criminal convictions permanently bar naturalisation, others bar it for a period, and some are conditional.

Beyond criminal matters, the areas that recur are failure to file tax returns, owing back taxes without a payment arrangement, failure to pay court-ordered child support, and failure to register for Selective Service where that applied. Several of these can often be resolved before filing — a documented IRS payment plan, for example, is treated very differently from an unaddressed tax debt.

Do not conceal anything. Providing false information on the application or at the interview is itself a bar and can result in citizenship being revoked years later if discovered. Arrests must be disclosed even where charges were dropped, records were expunged, or you were told it would not appear. Anyone with any criminal history should speak to an immigration attorney before filing, because some issues that seem minor are disqualifying and some that seem serious are not.

The English requirement covers reading, writing and speaking. Speaking ability is assessed throughout the interview rather than in a separate section, and the reading and writing components involve straightforward sentences on civics-related topics.

The civics test is oral, drawn from a published set of questions on US history and government, and you pass by answering correctly a set number of the questions asked. Because the questions are published in advance, this is a test you can prepare for thoroughly, and USCIS provides free study materials.

Exemptions exist and are widely underused. Applicants who are older and have held permanent residence for long periods may be exempt from English and may take the civics test in their own language, and there are further accommodations for those with qualifying medical conditions, which require a certified medical form.

Failing a test is not immediately fatal. Applicants who fail part of the interview testing are generally given a second opportunity within a defined window, retaking only the portion failed.

You apply on Form N-400, filed online or by post. Filing online is generally easier to track and reduces the risk of a package going astray.

Fees are set by USCIS and change periodically. Fee reductions and full waivers are available for applicants below certain income thresholds, and applying for one is a formal part of the process rather than a favour — but a waiver request that is not properly documented can delay the whole application.

Assemble supporting evidence carefully. This typically includes your green card, evidence of marital status where the three-year rule applies, tax records, travel history, and documentation of anything disclosed on the form. Incomplete evidence is a leading cause of requests for further information, which add months.

A biometrics appointment usually follows, at which fingerprints and a photograph are taken for background checks. In some cases USCIS reuses previously collected biometrics.

The interview is conducted by a USCIS officer who reviews your application with you under oath, asks about your background and eligibility, and administers the English and civics testing. Answers that contradict your written application are a serious problem, so reread your own form before attending.

Processing times vary substantially by field office and change over time. USCIS publishes current times by office, which is the only sensible place to get an expectation — figures quoted by friends or forums are usually out of date.

If approved, you take the Oath of Allegiance at a ceremony, which may be the same day or scheduled later. You are not a citizen until the oath is taken, and you surrender your green card at that point. You receive a Certificate of Naturalisation, which is your proof of citizenship and should be kept extremely safe — replacing it is slow and expensive.

If the application is denied, the decision explains why, and there is a formal process to request a hearing to review it. Some denials reflect a fixable problem and some mean waiting longer before reapplying.

Apply for a US passport soon after the ceremony. It is the most convenient proof of citizenship for everyday purposes and means your Certificate of Naturalisation can stay somewhere secure rather than travelling with you.

Update the Social Security Administration so your record reflects your citizenship status. This matters for employment verification and benefits.

You can register to vote as soon as you are a citizen, and voting is one of the few rights that naturalisation confers immediately and that permanent residence never did.

Naturalised citizens can hold federal jobs requiring citizenship, petition for a broader range of relatives to immigrate, and cannot be deported except in the rare circumstance where citizenship is revoked for fraud in obtaining it.

Whether you keep your original nationality depends entirely on the other country's law, not on US law. Some countries permit dual nationality, some automatically revoke citizenship on naturalisation elsewhere, and some require a formal declaration. Check with that country's embassy before the oath, particularly if you own property, expect to inherit, or may need to return for extended periods.

Immigration services fraud is widespread and specifically targets this process. In many countries a notario is a qualified lawyer, but in the United States a notary public is not — the mismatch is deliberately exploited. Only an attorney licensed in a US state or an accredited representative of a recognised organisation can give immigration legal advice.

Warning signs are consistent: guarantees of a particular outcome, requests to sign blank forms, refusal to give you copies of what was filed on your behalf, and advice to provide false information. Nobody can guarantee approval, and government forms are available free from USCIS — anyone charging you for the forms themselves is charging for something free.

Immigration court proceedings are handled by a separate agency within the Department of Justice rather than by USCIS, which is worth knowing if anything about your status is contested.