To send a letter to the IRS, write a signed letter that identifies you and your tax year, mail it to the address printed on the notice you’re answering (or the address the IRS publishes for your form and state if you’re not responding to a notice), and use Certified Mail or an IRS-approved private delivery service so the postmark protects your filing date. Get any of those three wrong and your letter can sit unmatched, land at the wrong processing center, or miss a deadline that costs you the right to dispute a tax.
What to Put in the Letter
The IRS handles a huge volume of mail, and staff need enough on the page to pull your account. Include your full legal name, current mailing address, Social Security Number or Individual Taxpayer Identification Number, and the tax year the letter concerns. Without those, your letter can drift.
If you’re answering a notice, put the notice or letter number near the top. You’ll find the CP or LTR number in the upper right of the IRS document.1Internal Revenue Service. Understanding Your IRS Notice or Letter That number tells the IRS which case your response belongs to.
Sign and date the letter. An unsigned response can be treated as if it was never filed. Attach copies of any supporting documents (receipts, wage statements, bank records) and keep the originals. Keep a full copy of everything you send.
Finding the Right Address
There is no single IRS mailing address. The correct one depends on what you’re sending, whether a payment is enclosed, and sometimes where you live.
Responding to a Notice
Use the response address printed on the notice itself. Every notice type routes to a specific office, and substituting a different IRS address (even one that worked before) can add weeks or months of delay.
Filing a Return or Form Without a Notice
For a paper return or IRS form, the address is in that form’s instructions. Addresses vary by form, by whether a payment is enclosed, and by the taxpayer’s state of residence. The IRS keeps a state-by-state directory for individual returns on its website.2Internal Revenue Service. Where to File Paper Tax Returns With or Without a Payment Check it for your specific form and state before mailing.
If You Live Abroad
Taxpayers living in a foreign country, using an APO or FPO address, or filing Form 2555 use separate addresses. Returns without a payment go to the Austin, TX processing center; returns with a check or money order go to the Charlotte, NC address.3Internal Revenue Service. U.S. Citizens and Resident Aliens Abroad Where and When to File and Pay
If You’re Enclosing a Payment
Make the check or money order payable to “U.S. Treasury.” On the check itself, write your name and address, a daytime phone number, the tax year, the related form or notice number (for example, “2025 Form 1040”), and the SSN or ITIN of the person who should receive credit for the payment.4Internal Revenue Service. Pay by Check or Money Order Never send cash.
When a payment is included, the mailing address is often different from the address for the same form filed without a payment; payments and non-payment correspondence go to different processing centers. Expect the check to clear fast. The IRS may convert it to an electronic fund transfer, so the money can leave your account the same day the IRS receives it.4Internal Revenue Service. Pay by Check or Money Order
How to Mail It So It Counts as On Time
Under federal tax law, the postmark date on your envelope counts as the filing date, even if the IRS receives the letter days later.5Office of the Law Revision Counsel. 26 USC 7502 – Timely Mailing Treated as Timely Filing and Paying That protection only applies if you use an approved method and the postmark falls on or before the deadline. Regular first-class mail with no tracking gives you nothing to prove either.
Certified and Registered Mail
Certified Mail through USPS is the practical choice for most IRS correspondence. You get a tracking number, delivery confirmation, and a dated mailing receipt. Adding a Return Receipt gives you a signed record of when the IRS took delivery. The Taxpayer Advocate Service specifically recommends certified mail with a return receipt for paper tax returns.6Taxpayer Advocate Service. Options for Filing a Tax Return
Registered Mail gives you a stronger legal presumption. The statute treats registration as prima facie evidence of delivery, and the registration date is treated as the postmark date.5Office of the Law Revision Counsel. 26 USC 7502 – Timely Mailing Treated as Timely Filing and Paying It costs more and moves slower, so most people reserve it for high-stakes filings.
Approved Private Delivery Services
The IRS designates specific service levels from DHL Express, FedEx, and UPS that satisfy the timely-mailing rule. Only certain expedited services qualify: FedEx Priority Overnight and 2 Day, UPS Next Day Air and 2nd Day Air, and DHL Express service levels are on the list, along with certain international options.7Internal Revenue Service. Private Delivery Services Ground services, economy shipping, and basic delivery options from these same carriers do not qualify. Pick the wrong service level and your filing is treated as received on the day the IRS physically opens it, not the day you shipped it.
Private delivery services also have to go to a physical street address, not a P.O. Box. The IRS publishes the street address for each processing center on its website.8Internal Revenue Service. Submission Processing Center Street Addresses for Private Delivery Service
After You Mail It
File your copy of the letter, the attachments, and the mailing receipt together. If you used Certified Mail or a private delivery service, use the tracking number to confirm delivery. That confirmation is your insurance if the IRS ever says it did not receive your filing.
Then wait. The IRS posts a running list of which months’ correspondence it is currently working through, and response times regularly stretch past two months; business correspondence can run six months or more.9Internal Revenue Service. Processing Status for Tax Forms Check that page before calling. And do not send a duplicate letter unless the IRS asks you to or unless a period well past the posted timeline has gone by. Duplicates create confusion on the account and slow things down.
What Happens If You Don’t Respond
Ignoring IRS correspondence is expensive. When you don’t respond to a notice proposing changes to your return, the IRS generally assesses the tax it thinks you owe and begins collection, and you lose the chance to dispute the amount or present evidence.
The most time-sensitive notice is the Notice of Deficiency, sometimes called the “90-day letter” (CP3219N is one example). After the IRS mails it, you have 90 days to file a petition with the U.S. Tax Court challenging the proposed tax; if you live outside the United States, the window is 150 days.10Office of the Law Revision Counsel. 26 USC 6213 – Restrictions Applicable to Deficiencies; Petition to Tax Court Filing a tax return does not extend this deadline.11Internal Revenue Service. Understanding Your CP3219N Notice Miss it and the IRS assesses the tax; your only remaining option is to pay first and then try to recover it through a refund claim.
Silence on other notices can trigger penalty assessments, interest charges, federal tax liens, and eventually wage garnishments or bank levies. The earlier you write back, the more options you have.
Having Someone Else Send Letters for You
If you want a tax professional, attorney, or family member to correspond with the IRS on your behalf, the agency requires a formal authorization. Form 2848, Power of Attorney and Declaration of Representative, lets a designated person represent you before the IRS, including signing and mailing correspondence.12Internal Revenue Service. Instructions for Form 2848 The person you name has to be eligible to practice before the IRS, such as an attorney, CPA, or enrolled agent.
If you only want someone to view your tax information without representing you, use Form 8821, Tax Information Authorization, instead. Naming a representative does not shift your tax obligations. You still owe any tax due.12Internal Revenue Service. Instructions for Form 2848
Form 2848 can be submitted online through IRS.gov, by fax, or by mail.13Internal Revenue Service. Submit Forms 2848 and 8821 Online Online submission is usually fastest and requires a Secure Access account. The correct mail and fax destinations are in the Form 2848 instructions and depend on where you live.