Yes, you can have no last name in the United States. No federal statute requires a surname, courts in most states will approve a petition to drop yours, and a majority of states still recognize the common law right to change your name by consistent use. The catch is that nearly every government database, ID document, and online form in the country is built around a first-and-last-name structure, so living as a mononym means constant workarounds at the SSA, the passport office, the DMV, the airline counter, and the new-hire paperwork on your first day of work.
What the Law Actually Requires
The federal government defines a “full legal name” as a given name, an optional middle name, and a family name, and that’s the structure the Social Security Administration, USCIS, and the State Department expect on every application.1U.S. Citizenship and Immigration Services. Chapter 5 – Verification of Identifying Information But no single federal law says you must carry a surname. The two-name convention is baked into administrative systems by habit and design, not by statute.
Birth registration is handled at the state level, and nearly every state’s birth certificate form includes a surname field. That’s why it’s difficult to be born without a last name in the U.S., even though the law doesn’t forbid it. For adults, the practical question is rarely whether the law allows a single name. It’s whether the bureaucracy can process one.
How to Legally Change Your Name to a Single Name
If you want to drop your surname and go by one name officially, the reliable route is a court-ordered name change. It’s the same process anyone uses to change a name, but expect the judge to look more carefully at an unusual request.
The Petition
You file a name change petition in the county where you live. It lists your current legal name, the name you want, your reason for the change, and supporting identity documents. Filing fees range from roughly $25 to $500 depending on the jurisdiction. Many states also require you to publish notice of the proposed change in a local newspaper, which typically adds $50 to $500 in publication costs.
After filing and publication, most jurisdictions hold a hearing. The judge’s core question is whether you’re acting in good faith and not trying to duck debts, a criminal record, or another obligation. Satisfy that and the judge signs an order legally establishing your new name.
When a Mononym Petition Draws Extra Scrutiny
Judges have wide discretion, and dropping your surname is unusual enough to get a second look. Beyond the fraud inquiry, a judge may weigh whether the new name will cause administrative confusion and whether the change serves a legitimate purpose. Cultural, religious, and philosophical grounds tend to help. Someone from a culture where single names are normal, or someone who has taken a religious name, stands on firmer ground than someone making the change on impulse. Courts have historically insisted that a legal name has to function as a name inside the legal system, which is why petitions for names made of numerals or symbols have failed. Single words don’t raise the same functional problems.
Common Law Name Changes
A majority of states still recognize the common law right to change your name simply by adopting a new one and using it consistently, provided you’re not doing it to defraud anyone. In theory you could start using a single name tomorrow without filing anything. In practice, a common law change gives you no court order to hand the SSA, the DMV, or the State Department, and without that order, updating your official records is much harder. Skipping the petition saves the filing fee and costs you months of friction at every agency counter.
What Your ID Documents Will Look Like
Every major federal system has a workaround for one-name people, and the pattern is consistent: your single name goes in the last name field, and the first name field gets a placeholder.
Social Security Card
SSA policy directs employees to enter a mononymous person’s name in the last name field of the record system. If an immigration document shows “FNU” for First Name Unknown, that acronym goes in the first name field.2Social Security. RM 10205.130 Entering Other Names of NH in SSNAP The Social Security card has two printed lines, 26 characters each for first/middle and last name, so a mononymous person’s card shows the name only on the second line.3Social Security Administration. RM 10205.120 How the Number Holder’s Name is Shown on SSN Card
U.S. Passport
The State Department follows International Civil Aviation Organization standards, which put a one-word name in the surname field on the passport’s data page and leave the given name field blank.4ICAO. TAG/TRIP/5-IP/4 Internally, the passport system marks the empty given name field so the entry reads as intentional rather than an error.5U.S. Department of State Foreign Affairs Manual (FAM). Name Usage and Name Changes Even if you think of your single name as a first name, on the passport it sits in the surname slot.
Where Daily Life Gets Complicated
The legal permissibility of a mononym and the practical experience of living with one are very different things. Federal agencies at least have documented procedures. Most of the private sector doesn’t.
Forms and Identity Verification
Online applications for banks, credit cards, landlords, and employers almost always require both a first and a last name, with validation rules that reject a blank field. You’ll end up typing “FNU” or a single period in the first name box and explaining the discrepancy to a person later. Some institutions won’t budge, and a credit application flagged for a name mismatch can turn into a denial, not just a delay.
Identity verification services that cross-check your name against credit bureaus, government records, and utility accounts rely on matching two-part names. A mononym fragments across those systems, so the same person can look like several people or like no one at all, depending on how each database handled the missing field. That inconsistency can affect credit scores, background checks, and fraud alerts in ways that are hard to predict.
Air Travel
Air travel is where the workarounds get tested. Your passport shows only a surname.5U.S. Department of State Foreign Affairs Manual (FAM). Name Usage and Name Changes Airline reservation systems typically require both first and last name fields. The standard practice for mononymous travelers is to enter the single name as the last name and “FNU” as the first name. TSA’s Secure Flight program requires the name on your reservation to match your government-issued ID exactly.6Transportation Security Administration. Does the Name on My Airline Reservation Have to Match the Name on My Application? Booking with “FNU” plus your actual name should line up with the passport data, but expect occasional confusion at online check-in or the gate. Some foreign immigration systems handle mononyms differently, and a passport with a blank given name field can trigger extra screening at border control in countries where single names are uncommon.
Getting Hired
Every new hire in the U.S. completes Form I-9. USCIS instructs employees who have only one legal name to enter it in the Last Name field and write “Unknown” in the First Name field.7U.S. Citizenship and Immigration Services. Completing Section 1 – Employee Information and Attestation If the employer runs E-Verify, the name has to match your SSA record. A mismatch between “Unknown” on the I-9 and whatever placeholder SSA used can produce a Tentative Nonconfirmation, which doesn’t stop you from working but starts a resolution process that costs time and paperwork. Payroll systems that split names into first and last fields can also cause your W-2 to diverge from your SSA record, and that triggers IRS matching notices.
Taxes
The IRS requires the name on your return to match your Social Security record exactly.8Internal Revenue Service. Name Changes and Social Security Number Matching Issues Form 1040 instructions don’t address mononyms, so mirror whatever appears on your Social Security card and be ready for the automated matching system to flag the return for review.
Updating Your Records After the Court Order
Once you have a signed court order, update your documents in a specific order, because most agencies verify your identity against the SSA record.9Social Security Administration. How Do I Change or Correct My Name on My Social Security Number Card?
- Start at the Social Security Administration. Bring the court order and current ID to a local SSA office and request a replacement card. SSA updates your Numident file and issues a new card.
- Take the court order and your new Social Security card to the DMV for a new driver’s license or state ID.
- Apply for a new passport through the State Department, submitting the court order with your application.
- Notify the IRS so your tax records line up, though the IRS generally pulls updated names from SSA automatically.8Internal Revenue Service. Name Changes and Social Security Number Matching Issues
- Provide copies of the court order to banks, employers, insurers, and schools.
Budget extra time for each step. Agencies that process thousands of standard name changes a day may never have seen a mononym, and frontline staff often need a supervisor to approve manual overrides. Bringing a printed copy of the relevant policy, whether that’s the SSA’s POMS reference or the State Department’s FAM section on one-word names, can keep a confused clerk from turning you away.