IRS documents (Form 6166, letters) Apostille: US Department of State Process (2026)
A irs documents (form 6166, letters) is a federal document — no state can apostille it. It goes to the U.S. Department of State — Office of Authentications: $20 per document, Form DS-4194, roughly 5+ weeks by mail or 2–3 weeks via Washington, DC walk-in. For non-Hague destinations, the same office issues an authentication certificate that then needs embassy legalization.
| Office | U.S. Department of State — Office of Authentications |
|---|---|
| Fee | $20 per document |
| Form | DS-4194 |
| Mail to | U.S. Department of State, Office of Authentications, 44132 Mercure Circle, PO Box 1206, Sterling, VA 20166-1206 |
| Walk-in | 600 19th Street NW, Washington, DC 20006 |
| Times | Mail 5+ weeks · walk-in 2–3 weeks |
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Step 1 — Get the document itself
Request Form 6166 by filing Form 8802 with the IRS, or obtain the IRS letter.
Step 2 — Complete Form DS-4194 and mail (or walk in)
Send the document with Form DS-4194 and $20 per document to U.S. Department of State, Office of Authentications, 44132 Mercure Circle, PO Box 1206, Sterling, VA 20166-1206. For faster service, drop it off at 600 19th Street NW, Washington, DC 20006 (2–3 weeks).Same-day appointments are reserved for documented emergencies with foreign travel inside two weeks.
Hague vs non-Hague destinations
If your destination is a Hague Apostille Convention member, you get an apostille and you are done. If not, you get an authentication certificate and then legalize it at that country's embassy. Check your destination with the Country Checker.
The #1 mistake: sending federal documents to a state
Common rejection reasons
- A tax transcript was submitted instead of the 6166 certificate
- The 6166 covers the wrong tax year
Frequently asked questions
＋Can a state apostille my irs documents (form 6166, letters)?
No. A irs documents (form 6166, letters) is a federal document, so it goes only to the U.S. Department of State — Office of Authentications — never a Secretary of State. Sending it to a state causes an automatic rejection and lost weeks.
＋How much does it cost and how long does it take?
The fee is $20 per document. Mail processing runs about 5+ weeks; a Washington, DC walk-in takes 2–3 weeks. Add embassy time for non-Hague destinations.
＋What do I actually send in?
Request Form 6166 by filing Form 8802 with the IRS, or obtain the IRS letter. Then include Form DS-4194, the $20 fee per document, and a prepaid return envelope.
＋What if my irs documents (form 6166, letters) is going to a non-Hague country?
The same office issues an authentication certificate instead of an apostille. You then legalize it at the destination country's embassy. The Country Checker shows the full chain.
Other federal documents
Sources
Reviewed by Billy Reiner, Editor
Last verified: July 13, 2026 against the U.S. Department of State — Office of Authentications (travel.state.gov)(official page). See how we verify and how often on ourmethodology page.
This is informational, not legal advice. The receiving authority sets the final requirements — confirm with them and the office named above before you send anything.