The A-Number (Alien Registration Number) is the number USCIS uses to identify your immigration records. Our guides on immigration court lookups, ICE bonds and USCIS forms all ask for it. This page sets out what USCIS’s own form instructions say about where to find it, what it looks like, and the numbers it gets confused with. It is general information, not legal advice.
Quick summary: The A-Number begins with the letter A and appears on correspondence from DHS or USCIS (I-90 and I-765 instructions). On a green card, it is printed on the front or back, depending on when the card was issued (N-400 instructions). It has 7 to 9 digits; when a form wants nine, add leading zeros (A1234567 → A001234567). The USCIS Number is the same as the A-Number (Form I-9 instructions). It is not your USCIS Online Account Number and not your receipt number. No A-Number: write N/A. Checked October 21, 2026.
Where the A-Number appears
| Document | What USCIS says | Source |
|---|---|---|
| Letters from DHS or USCIS | The A-Number begins with an A and can be found on correspondence you have received from DHS or USCIS | Form I-90 instructions; Form I-765 instructions |
| Green card (Permanent Resident Card, formerly the Alien Registration Card) | The A-Number is on the card; it “may be located on the front or back of your card, depending on when the card was issued” | Form N-400 instructions |
| The USCIS Number on a card or form | The same number: “USCIS Number (A-Number)” | Form I-9 instructions |
| Immigration court papers | EOIR prints it on DHS and EOIR correspondence; see our EOIR case lookup guide | EOIR (see that page) |
If you have a green card, start there. If you are still in process, look at the letters you have from USCIS or DHS.
What it looks like, and how to write it on a form
- Letter A, then digits. The N-400 instructions say the A-Number on your card has seven to nine digits, depending on when your record was created. The Form I-9 instructions also describe a 7- to 9-digit number.
- Padding to nine digits. When a form has nine boxes, the N-400 instructions say to put enough zeros before the first number to make nine digits:
| On your card | On a 9-digit form |
|---|---|
| A1234567 (7 digits) | A001234567 |
| A12345678 (8 digits) | A012345678 |
| A123456789 (9 digits) | A123456789 |
The examples in the first two rows are USCIS’s own. The third row shows a nine-digit number, which needs no zeros. The immigration court phone line has its own entry rule; it is on our EOIR guide.
Numbers that are not your A-Number
| Number | What it is | Is it the A-Number? |
|---|---|---|
| USCIS Number | The name the Form I-9 instructions use for the same number | Yes, the same number |
| USCIS Online Account Number (OAN) | Only exists if you filed a form with a receipt number beginning with IOE; shown in your online account profile, or on the Account Access Notice if you filed on paper | No, per the I-90 and I-765 instructions |
| Receipt number | Identifies one application or petition; printed on USCIS notices | No; see USCIS case status and receipt numbers |
If you have never had one, or cannot find it
- Never had one. Form instructions such as the I-90 and I-765 say to type or print N/A in the A-Number field if you do not have one.
- Had one, cannot find it. Go through the letters you have from USCIS, DHS or the immigration court. For naturalization, the N-400 instructions say USCIS needs both your A-Number and your permanent resident date, and that if you do not have them you should contact the USCIS Contact Center to get them before you file.
- Ask for your file. A Freedom of Information Act (FOIA) request is the route to a copy of your immigration records. See requesting your immigration records (FOIA).
Where you will be asked for it
| Task | Our guide |
|---|---|
| Check a case in immigration court (online or by phone) | Check an immigration court case (EOIR) |
| Pay an ICE immigration bond for a detained relative | Pay an ICE bond |
| Find a relative held by ICE | Consular assistance if detained or hospitalized |
| Renew or replace a green card | Form I-90 |
| Apply for or renew a work permit | Form I-765 |
| Apply for citizenship | Form N-400 |
Related
- USCIS case status and receipt numbers
- US alien registration requirement
- Family preparedness plan if a parent is detained
- All diaspora guides
Sources
- USCIS, Instructions for Form I-90 (OMB expiration 02/28/2027): https://www.uscis.gov/sites/default/files/document/forms/i-90instr.pdf (read October 21, 2026)
- USCIS, Instructions for Form I-765 (OMB expiration 08/31/2027): https://www.uscis.gov/sites/default/files/document/forms/i-765instr.pdf (read October 21, 2026)
- USCIS, Instructions for Form N-400 (OMB expiration 02/28/2027): https://www.uscis.gov/sites/default/files/document/forms/n-400instr.pdf (read October 21, 2026)
- USCIS, Instructions for Form I-9 (01/20/25 edition; OMB expiration 05/31/2027): https://www.uscis.gov/sites/default/files/document/forms/i-9instr.pdf (read October 21, 2026)
Frequently Asked Questions
Where can I find my A-Number?
USCIS’s form instructions say the A-Number begins with an A and can be found on correspondence you have received from DHS or USCIS. If you are a permanent resident, the N-400 instructions say it is on your Permanent Resident Card (green card), on the front or the back depending on when the card was issued.
How many digits does an A-Number have?
Seven to nine digits, depending on when your record was created, according to the N-400 instructions. The Form I-9 instructions also describe it as a 7- to 9-digit number. When a form asks for nine digits, the N-400 instructions say to put zeros before the first number: A1234567 becomes A001234567 and A12345678 becomes A012345678.
Is the USCIS Number on my green card the same as my A-Number?
Yes. The Form I-9 instructions call it the USCIS Number (A-Number), and the N-400 instructions write A-Number (USCIS Number).
Is my USCIS online account number my A-Number?
No. The I-90 and I-765 instructions say the USCIS Online Account Number is not the same as an A-Number. You only have an online account number if you filed a form with a receipt number beginning with IOE. Your receipt number, printed on USCIS notices, is a third, different number.
What if I have never had an A-Number?
Form instructions such as the I-90 and I-765 say that if you do not have an A-Number, you type or print N/A in that field.
I cannot find my A-Number. What can I do?
Check the letters you have from DHS, USCIS or the immigration court. The N-400 instructions tell naturalization applicants who do not have their A-Number or permanent resident date to contact the USCIS Contact Center to get it before filing. A FOIA request for your immigration records is another route; see our FOIA guide.
