USPS RTO Lookup by ZIP Code
Is your post office on USPS's Regional Transportation Optimization (RTO) list?
Type a ZIP code to see its post office, whether the RTO truck change has started there, and the last day to mail.
The data is USPS's own, from its filings at the Postal Regulatory Commission: 28,540 ZIP codes, updated with the report of October 1, 2026.
Is Your Post Office on the RTO List?
Type the ZIP code the mail is sent from.
You get its post office and assigned plant, whether the truck change (LTO or RTO) has started there, and what it means for your mail.
Prefer a map? Watch the truck change spread on our RTO map, month by month. Save the Post Office also keeps an RTO map by ZIP code, updated every month.
USPS data: RTO list of January 16, 2026, monthly report of October 1, 2026.
Last Day to Mail
- Being on the list does not set the days by itself: USPS says both ZIP codes count.
- Add where the mail is going and the day it must arrive.
- The dates use USPS's July 2026 standards, with the extra day for offices far from their plant included.
The day it must be delivered.
What Is USPS RTO?
RTO (Regional Transportation Optimization) is a USPS change for post offices more than 50 miles from their regional processing plant.
Before: two trucks a day. One in the morning with mail to deliver, one later to take the day's outgoing mail to the plant.
Now: typically one trip a day. Outgoing mail leaves the next morning instead of the same evening.
Before February 2025, USPS called the same change LTO (Local Transportation Optimization). It began in October 2023.
The extra day
- Since April 1, 2025, USPS adds one day for First-Class Mail and Ground Advantage sent from offices more than 50 miles from their regional plant.
- It applies even where the truck change has not started yet.
- Presorted First-Class Mail is not changed.
What does not change
- Post office hours.
- Carrier delivery and pickups, and collection from blue boxes.
- Only the time the mail leaves for the plant changes (USPS).
Not every route slows down
- USPS says the days still depend on both ZIP codes.
- From some RTO offices, 2-day mail stays 2-day, while 3-day mail becomes 4-day and 4-day becomes 5-day (Save the Post Office explains why).
- That is why the calculator above uses your exact route.
The review
- The Postal Regulatory Commission reviewed the plan in docket N2024-1 and gave its advisory opinion on January 31, 2025.
Sources: USPS, Changes in Service Standards: FAQs (updated February 9, 2026); Postal Regulatory Commission, Nationwide Changes to Mail Service.
Our Finding: USPS's Slower-ZIP List Is Almost All RTO ZIP Codes
13,286 of the 13,333 ZIP codes on USPS's slower list for First-Class Mail (99.6%) are on the RTO list.
The slower list is in USPS's Supplemental Service Standard Directory (July 2026). It names the ZIP codes whose mail takes longer than the rest of their 3-digit area.
We compared it with USPS's RTO list, ZIP code by ZIP code.
| Mail class | ZIP codes on the slower list | On the RTO list | Share |
|---|---|---|---|
| First-Class Mail | 13,333 | 13,286 | 99.6% |
| Ground Advantage | 10,562 | 10,515 | 99.6% |
| Priority Mail | 22,541 | 10,694 | 47.4% |
What it means
- For First-Class Mail and Ground Advantage, almost every ZIP code on USPS's slower list is an RTO ZIP code. This is the extra day USPS added in 2025.
- The slower list only shows ZIP codes that differ from the rest of their 3-digit area. Many RTO ZIP codes get the extra day through their whole area's standard instead, so they are not on this list. For example, nearly all of New Hampshire is RTO, so its 3-digit areas carry the extra day in the base standard (Save the Post Office).
- The day was added whether or not the truck change had started. By the report of October 1, 2026, the change (LTO or RTO) had started in 8,120 of the 13,333 slower First-Class Mail ZIP codes.
- Priority Mail's slower list is different: fewer than half of its ZIP codes are RTO ZIP codes.
How we checked
- 5-digit ZIP codes, exactly as USPS lists them in both files.
- The RTO list here is the 28,540 ZIP codes of January 16, 2026, plus 5 more that appear only in the report of October 1, 2026.
- You can check it yourself with the free download below.
RTO by State
- USPS's list has post offices in all 48 states of the lower 48.
- Alaska, Hawaii, the District of Columbia and Puerto Rico have none.
- Most RTO ZIP codes: Texas (1,697), then New York (1,497) and Pennsylvania (1,362).
- "Truck change started" counts the ZIP codes with an LTO or RTO date in the report of October 1, 2026.
| State | Post offices | ZIP codes | Truck change started |
|---|---|---|---|
| Alabama | 456 | 631 | 328 |
| Arizona | 226 | 319 | 183 |
| Arkansas | 565 | 685 | 492 |
| California | 888 | 1,251 | 797 |
| Colorado | 321 | 441 | 182 |
| Connecticut | 172 | 286 | 0 |
| Delaware | 46 | 75 | 0 |
| Florida | 425 | 725 | 203 |
| Georgia | 542 | 710 | 244 |
| Idaho | 206 | 250 | 205 |
| Illinois | 903 | 1,130 | 688 |
| Indiana | 504 | 722 | 339 |
| Iowa | 668 | 865 | 297 |
| Kansas | 478 | 664 | 544 |
| Kentucky | 521 | 798 | 228 |
| Louisiana | 494 | 710 | 331 |
| Maine | 314 | 359 | 324 |
| Maryland | 239 | 315 | 264 |
| Massachusetts | 185 | 225 | 87 |
| Michigan | 630 | 779 | 604 |
| Minnesota | 585 | 720 | 535 |
| Mississippi | 409 | 496 | 0 |
| Missouri | 620 | 880 | 539 |
| Montana | 299 | 369 | 156 |
| Nebraska | 394 | 517 | 420 |
| Nevada | 96 | 140 | 61 |
| New Hampshire | 207 | 260 | 216 |
| New Jersey | 180 | 218 | 178 |
| New Mexico | 278 | 354 | 101 |
| New York | 1,195 | 1,497 | 904 |
| North Carolina | 595 | 774 | 406 |
| North Dakota | 248 | 372 | 79 |
| Ohio | 707 | 946 | 556 |
| Oklahoma | 483 | 618 | 262 |
| Oregon | 296 | 351 | 298 |
| Pennsylvania | 1,055 | 1,362 | 1,108 |
| Rhode Island | 54 | 79 | 62 |
| South Carolina | 303 | 415 | 243 |
| South Dakota | 294 | 382 | 184 |
| Tennessee | 437 | 563 | 83 |
| Texas | 1,255 | 1,697 | 850 |
| Utah | 158 | 208 | 52 |
| Vermont | 262 | 309 | 257 |
| Virginia | 651 | 927 | 561 |
| Washington | 330 | 393 | 334 |
| West Virginia | 595 | 847 | 637 |
| Wisconsin | 598 | 715 | 642 |
| Wyoming | 139 | 191 | 58 |
| Total | 21,506 | 28,540 | 16,122 |
When the Truck Change Started: ZIP Codes by Month
- The change began as LTO in October 2023. USPS's report says LTO starts ended in January 2025 and RTO starts began in February 2025.
- By the report of October 1, 2026, it had started in 16,127 ZIP codes (3,443 with an LTO date, 13,876 with an RTO date), most recently in September 2026.
- USPS's report notes there were no RTO starts in April 2025 or December 2025.
- Watch it on the map, month by month.
- Each ZIP code is counted in the month the change started there: its LTO date, or else its RTO date. 1,392 ZIP codes have more than one date in the report; the lookup shows them all.
- About 200 ZIP codes have two RTO dates. Save the Post Office believes the later one is a correction, so we use it.
| Month | ZIP codes |
|---|---|
| October 2023 | 281 |
| January 2024 | 573 |
| February 2024 | 540 |
| March 2024 | 328 |
| May 2024 | 208 |
| June 2024 | 292 |
| July 2024 | 453 |
| August 2024 | 335 |
| November 2024 | 102 |
| January 2025 | 331 |
| March 2025 | 1,401 |
| May 2025 | 2,904 |
| June 2025 | 67 |
| July 2025 | 815 |
| August 2025 | 821 |
| September 2025 | 450 |
| October 2025 | 971 |
| November 2025 | 306 |
| January 2026 | 1,687 |
| February 2026 | 147 |
| March 2026 | 489 |
| April 2026 | 1,100 |
| May 2026 | 510 |
| June 2026 | 37 |
| July 2026 | 102 |
| August 2026 | 545 |
| September 2026 | 332 |
Mailing a Ballot From an RTO ZIP Code
The general election is on Tuesday, November 3, 2026.
USPS's advice for every voter
- Mail the completed ballot before Election Day.
- Mail it at least one week before your election office must receive it.
- Some states ask for more time.
From an RTO post office
- Where the truck change has started, outgoing mail leaves for the plant the next morning.
- USPS says a ballot envelope may not get its postmark on the day it is collected.
- To be sure of that day's postmark: hand the envelope in at the post office counter and ask for a manual (hand) postmark. It is free.
Your state's rules
- This page gives mail timing only.
- For your deadline and the rules, check your state's election office at usa.gov/election-office.
Source: USPS Election Mail and the USPS FAQ above.
Download the RTO ZIP Code List
One row per ZIP code (28,545 rows), with:
- the ZIP code, its post office and address, and the state
- its assigned regional plant (RPDC)
- whether it is on the list of January 16, 2026
- its LTO and RTO start dates, from the report of October 1, 2026
- Free to use. Please credit "deliverytimecalculator.com, from USPS filings at the Postal Regulatory Commission".
- To link to one ZIP code's answer, add ?zip= and the ZIP code: /usps-rto-lookup?zip=12574
Sources
- The RTO list: USPS response to ACR2025 Chairman's Information Request No. 1, question 28 (Postal Regulatory Commission filing 139072, January 16, 2026). USPS does not publish this list on usps.com.
- Where the truck change has started (LTO and RTO dates): USPS Eighteenth Report, docket RM2024-9 (filing 140996, October 1, 2026). USPS files a new report every month; we update this page when it does.
- The rules: USPS, Changes in Service Standards: FAQs (updated February 9, 2026).
- The slower ZIP codes: USPS Supplemental Service Standard Directory, July 2026 (postalpro.usps.com), the same data our calculators use.
- Thanks to Save the Post Office, which pointed us to these filings and has followed RTO since the start, with its own RTO map.
Frequently Asked Questions
What is USPS RTO?
RTO (Regional Transportation Optimization) is a USPS change for post offices more than 50 miles from their regional processing plant.
USPS used to send two trucks a day to each of these post offices; under RTO there is typically one, so outgoing mail collected during the day goes to the plant the next morning instead of the same evening.
How do I know if my post office is on the RTO list?
Type your ZIP code in the lookup on this page.
USPS does not publish the list on usps.com; it gave it to the Postal Regulatory Commission on January 16, 2026 (21,506 post offices serving 28,540 ZIP codes) and reports every month where RTO has started.
Does RTO slow down my mail?
It can slow down mail you send from an RTO post office.
Since April 1, 2025, USPS adds one day to its delivery standard for First-Class Mail and Ground Advantage sent from offices more than 50 miles from their regional plant, even where the truck change has not started yet; presorted business mail is not changed.
Not every route gets it: from some of these offices, 2-day mail stays 2-day, while 3-day mail becomes 4-day and 4-day becomes 5-day. The calculator on this page gives the dates for your exact route.
Does RTO slow down mail I receive?
Mail sent to you from a post office on the RTO list can take an extra day, because USPS adds it where mail is sent from. Your own post office being on the list does not slow mail sent to you from other places.
What is LTO?
LTO (Local Transportation Optimization) was USPS's name for the same truck change before February 2025.
USPS's monthly report has an LTO date column (October 28, 2023 to January 11, 2025) and an RTO date column (since February 2025). A ZIP code with either date has the truck change, and the lookup shows both.
Which plant does my mail go through?
The plant the lookup shows is the regional processing and distribution center (RPDC) USPS assigned to the post office. USPS uses the distance to it to decide RTO status.
Many RPDCs are not open yet (about 15 of 59 by September 2026, according to Save the Post Office), so for now the mail may still go through another plant.
Does RTO change post office hours or blue box pickups?
No. USPS says RTO does not change post office hours, carrier delivery or pickups, or collection from blue boxes. What changes is when the collected mail leaves for the processing plant.
How should I mail a ballot from an RTO post office?
USPS's advice for all voters: mail your completed ballot before Election Day and at least one week before your election office must receive it.
To be sure of that day's postmark, hand it in at the post office counter and ask for a manual postmark, which is free. Always check your state's rules.