You're staring at the calendar. It’s mid-April, or maybe you're dealing with a disaster area declaration that shifted the goalposts, and the panic is starting to set in. You need more time. You’ve downloaded the PDF. You’ve filled out the basic info. But now comes the part that feels surprisingly like 1995: you have to stick it in an envelope and hope it gets to the right IRS building. Knowing where to mail extension form 4868 isn't just about finding an address; it's about making sure your request actually counts so you don't get slapped with a late-filing penalty that eats into your savings.
Tax season is a grind. Honestly, the IRS website can be a maze of "if-then" scenarios that make your head spin. If you live in New York, you send it one place. If you're in Texas, it goes somewhere else. And if you’re sending a check? Well, that changes the zip code entirely.
The Geography of Tax Extensions
The IRS doesn't have one giant mailbox. They have processing centers scattered across the country, and they divide the workload based on where you live. This is usually the part where people get tripped up. If you are mailing your Form 4868 because you can't or won't use the e-file system, you have to be precise.
Let's say you live in Florida, Louisiana, Mississippi, or Texas. If you aren't enclosing a payment—meaning you’re just asking for the extra six months—you’re sending that envelope to the Department of the Treasury, Internal Revenue Service, Austin, TX 73301-0045. But wait. If you are including a check or money order because you know you owe Uncle Sam a bit of cash, that address changes. You'd send it to a P.O. Box in Charlotte, North Carolina. Specifically, P.O. Box 1236, Charlotte, NC 28201-1236.
It feels counterintuitive. Why send a Texas resident's payment to North Carolina? It’s basically about how the IRS handles "lockbox" payments versus paper processing. They want the money to go to a bank-operated facility so it clears faster.
For those up in the Northeast—think Maine, Massachusetts, New Hampshire, Vermont—the destination is different. No payment? Send it to Kansas City, MO 64999-0045. Making a payment? That goes to Louisville, Kentucky.
Does it actually matter which one you use?
Yes. 100%. If you send your extension to the wrong service center, the IRS will eventually forward it to the right one, but the "received" date might be delayed. If it arrives after the deadline because you sent it to the California center instead of the Missouri one, you might have to fight a penalty. It's a headache you don't need.
Why People Still Use Snail Mail
You might wonder why anyone still licks a stamp in 2026. E-filing is faster. It gives you a digital receipt. Yet, plenty of people still search for where to mail extension form 4868 because they have a specific reason to stay offline.
Maybe you’re a "paper trail" person. There is a certain security in having a physical copy of a form with a certified mail receipt in your hand. If the IRS ever claims they never heard from you, that little white and green slip from the post office is your "get out of jail free" card.
Or maybe the IRS systems are down. It happens. High traffic on April 15th can make the Free File websites crawl to a halt. In those moments, the blue USPS box on the corner is the only reliable backup.
There are also nuanced situations. If you are living abroad and have a foreign address, your mailing instructions are entirely different. You’ll be sending your form to the International Operations unit in Austin, Texas, regardless of whether you're in Paris or Perth.
The Registered Mail Secret
If you are going to mail this thing, do not just drop it in a mailbox with a forever stamp and hope for the best. Use Certified Mail, Return Receipt Requested.
It costs a few extra bucks. It’s worth every penny.
The Internal Revenue Code Section 7502 contains what’s known as the "Timely Mailing Treated as Timely Filing" rule. Basically, if the postmark on your envelope is on or before the due date, it’s considered on time, even if it doesn't land on an IRS desk until a week later. But—and this is a big "but"—if the IRS loses it and you don't have a certified mail receipt, you have no legal proof you sent it. A regular stamp won't save you in tax court.
Breaking Down the Address List
Because the IRS updates these locations occasionally, you should always double-check the back of the current year’s Form 4868 instructions. However, the general regional split has remained fairly stable.
If you reside in Alaska, Arizona, California, Colorado, Hawaii, Idaho, New Mexico, Nevada, Oregon, Utah, Washington, or Wyoming:
- Without payment: Department of the Treasury, Internal Revenue Service, Ogden, UT 84201-0045.
- With payment: Internal Revenue Service, P.O. Box 80109, Cincinnati, OH 45280-0109.
If you are in the Midwest or South—places like Alabama, Arkansas, Illinois, Indiana, Iowa, Kansas, Kentucky, Michigan, Minnesota, Missouri, Montana, Nebraska, North Dakota, Oklahoma, South Dakota, Tennessee, West Virginia, or Wisconsin:
- Without payment: Department of the Treasury, Internal Revenue Service, Kansas City, MO 64999-0045.
- With payment: Internal Revenue Service, P.O. Box 931300, Louisville, KY 40293-1300.
For the East Coast and Mid-Atlantic, including Connecticut, Delaware, District of Columbia, Georgia, Maryland, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Virginia:
- Without payment: Department of the Treasury, Internal Revenue Service, Kansas City, MO 64999-0045.
- With payment: Internal Revenue Service, P.O. Box 931300, Louisville, KY 40293-1300.
Wait, did you notice that? Kansas City handles the bulk of the "no payment" extensions for almost half the country now. They've consolidated a lot of their paper processing operations over the last few years.
Common Mistakes That Nullify Your Extension
Finding where to mail extension form 4868 is only half the battle. If the form is junk, the extension is junk.
First, the extension is for filing, not for paying. This is the biggest myth in taxes. If you owe $5,000 and you file an extension without paying, the IRS is going to start charging you interest from the original due date. They won't reject the extension, but they will send you a bill for the interest and the "failure to pay" penalty.
Second, accuracy on the form matters. If you put the wrong Social Security Number or your name doesn't match what the Social Security Administration has on file (maybe you got married and didn't update your name), the IRS system might kick it out.
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Third, the signature. Well, actually, here’s a fun fact: you don't actually have to sign Form 4868 if you are mailing it. Check the instructions. It's one of the few IRS forms that doesn't require a signature. But you do have to estimate your tax liability. You can't just put zeros if you know you earned money. You have to make a "proper estimate" based on the info you have. If you purposefully lowball that number to avoid a penalty, the IRS can technically void your extension. They rarely do it for small mistakes, but if it's egregious, they have the power.
What about the "Voucher"?
When you print out Form 4868, you’ll see a little perforated section at the bottom. That’s the 4868-V (Voucher). If you’re mailing a check, you cut that off and include it. Don't staple the check to the voucher. Don't paperclip it. Just put them loose in the envelope. Write your SSN, "2025 Form 4868" (or whatever tax year you are filing for), and your phone number on the check itself.
Special Cases: Disasters and Combat Zones
Sometimes, the standard rules for where to mail extension form 4868 are superseded by life. If you are in a federally declared disaster area—say, a hurricane hit your county in Florida or a wildfire swept through California—the IRS often grants automatic extensions.
In these cases, you might not even need to mail Form 4868. They identify taxpayers in those zip codes and move the deadline automatically. However, if you want to be safe, you can still mail the form. Just write the name of the disaster (e.g., "Hurricane Helene") in red ink at the top of the form so the processor knows why you might be "late" by the standard calendar.
For military members in combat zones, the rules are even more generous. You usually get at least 180 days after you leave the combat zone to file. You don't even need to file Form 4868 in many of those cases, but keeping the IRS in the loop with a letter or the form is never a bad idea.
Wrapping This Up Properly
Getting your extension in the mail is about peace of mind. It buys you time to find those lost 1099s or wait for that K-1 that always arrives late.
To make sure this works:
- Double-check the address based on whether you are sending money.
- Go to the post office and get a Certified Mail receipt.
- Estimate your taxes honestly, even if you can't pay them all right now.
- Keep a copy of the filled-out form for your records.
Once you’ve dropped that envelope in the mail, you can breathe. You have until October 15th to get your actual return finished. Just remember that the clock is still ticking on any interest for unpaid balances, so try to finish the actual filing as soon as you have your paperwork in order. If you're looking for the most current addresses or need to see if your specific state has different rules for state-level extensions, checking the "Where to File" page on IRS.gov is always the smart final step before you seal the envelope.