Every tax return processed by the IRS is tagged with a hidden identifier that most taxpayers never notice—but IRS systems rely on constantly. That identifier is the Document Locator Number, commonly referred to as the DLN.
Understanding the IRS Document Locator Number DLN can help explain where your return is being processed, which IRS service center controls it, and how the IRS finds your return if it is pulled for review.
The Document Locator Number (DLN) is a 14-digit number assigned to every tax document that posts to the IRS Master File.
The DLN acts as:
Once assigned, the DLN stays with the return throughout its life cycle.
While taxpayers focus on refund dates and transcript codes, IRS employees rely on the DLN to:
If a return is delayed or pulled for review, the DLN is how the IRS finds it quickly.
Each section of the DLN has a specific meaning.
The first two digits identify which IRS Service Center originally processed the return.
Examples include:
This tells you where your return entered the IRS pipeline.
| DLN Code | IRS Service Center / Campus | Common Notes |
|---|---|---|
| 01 | Andover, MA | Legacy processing campus |
| 02 | Atlanta, GA | Legacy processing campus |
| 03 | Austin, TX | Active campus for individual and business returns |
| 04 | Brookhaven, NY | Legacy processing campus |
| 05 | Cincinnati, OH | Active campus, frequent IMF processing |
| 06 | Fresno, CA | Active campus, high-volume individual returns |
| 07 | Kansas City, MO | Active campus for IMF and BMF |
| 08 | Memphis, TN | Legacy processing campus |
| 09 | Philadelphia, PA | Active campus, notices and adjustments |
| 10 | Detroit, MI | Legacy / reassigned operations |
| 11 | Martinsburg, WV | Enterprise Computing Center (ECC) support |
| 12 | Ogden, UT | Active campus, transcripts and adjustments |
| 13 | Philadelphia, PA | Alternate Philly routing |
| 14 | Richmond, VA | Legacy processing campus |
| 20 | Modernized IMF Routing | Common for CADE2-era processing |
| 89 | Submission Processing Support | Internal routing / special handling |
If your DLN begins with:
This helps explain why two taxpayers who filed on the same day may experience different processing speeds.
When a return is:
The service center code determines:
This is why IRS agents often reference “the campus” when discussing delays.
This digit identifies the type of tax document.
Common examples:
These digits identify the specific form or return category, such as:
This helps the IRS distinguish between different filings tied to the same taxpayer.
The Julian date represents the day of the year the return was processed.
For example:
This gives insight into when your return entered active processing.
The IRS often uses Julian dates inside systems like DLNs, processing logs, and internal posting schedules. A Julian date represents the day number of the year, from 001 to 365 (2026 is not a leap year).
| Date | Julian |
|---|---|
| Jan 1 | 001 |
| Jan 5 | 005 |
| Jan 10 | 010 |
| Jan 15 | 015 |
| Jan 20 | 020 |
| Jan 25 | 025 |
| Jan 31 | 031 |
| Date | Julian |
|---|---|
| Feb 1 | 032 |
| Feb 5 | 036 |
| Feb 10 | 041 |
| Feb 15 | 046 |
| Feb 20 | 051 |
| Feb 25 | 056 |
| Feb 28 | 059 |
| Date | Julian |
|---|---|
| Mar 1 | 060 |
| Mar 5 | 064 |
| Mar 10 | 069 |
| Mar 15 | 074 |
| Mar 20 | 079 |
| Mar 25 | 084 |
| Mar 31 | 090 |
| Date | Julian |
|---|---|
| Apr 1 | 091 |
| Apr 5 | 095 |
| Apr 10 | 100 |
| Apr 15 | 105 |
| Apr 20 | 110 |
| Apr 25 | 115 |
| Apr 30 | 120 |
| Date | Julian |
|---|---|
| May 1 | 121 |
| May 5 | 125 |
| May 10 | 130 |
| May 15 | 135 |
| May 20 | 140 |
| May 25 | 145 |
| May 31 | 151 |
| Date | Julian |
|---|---|
| Jun 1 | 152 |
| Jun 5 | 156 |
| Jun 10 | 161 |
| Jun 15 | 166 |
| Jun 20 | 171 |
| Jun 25 | 176 |
| Jun 30 | 181 |
| Date | Julian |
|---|---|
| Jul 1 | 182 |
| Jul 5 | 186 |
| Jul 10 | 191 |
| Jul 15 | 196 |
| Jul 20 | 201 |
| Jul 25 | 206 |
| Jul 31 | 212 |
| Date | Julian |
|---|---|
| Aug 1 | 213 |
| Aug 5 | 217 |
| Aug 10 | 222 |
| Aug 15 | 227 |
| Aug 20 | 232 |
| Aug 25 | 237 |
| Aug 31 | 243 |
| Date | Julian |
|---|---|
| Sep 1 | 244 |
| Sep 5 | 248 |
| Sep 10 | 253 |
| Sep 15 | 258 |
| Sep 20 | 263 |
| Sep 25 | 268 |
| Sep 30 | 273 |
| Date | Julian |
|---|---|
| Oct 1 | 274 |
| Oct 5 | 278 |
| Oct 10 | 283 |
| Oct 15 | 288 |
| Oct 20 | 293 |
| Oct 25 | 298 |
| Oct 31 | 304 |
| Date | Julian |
|---|---|
| Nov 1 | 305 |
| Nov 5 | 309 |
| Nov 10 | 314 |
| Nov 15 | 319 |
| Nov 20 | 324 |
| Nov 25 | 329 |
| Nov 30 | 334 |
| Date | Julian |
|---|---|
| Dec 1 | 335 |
| Dec 5 | 339 |
| Dec 10 | 344 |
| Dec 15 | 349 |
| Dec 20 | 354 |
| Dec 25 | 359 |
| Dec 31 | 365 |
The final digits are a unique sequence number assigned that day.
This ensures that:
Think of it as the return’s serial number.
The DLN commonly appears on:
It is usually labeled simply as “DLN” or embedded in transcript entries.
If a return is:
The DLN tells the IRS technician exactly where the return is stored—digitally or physically.
This is why older or paper-related cases often reference DLNs during correspondence.
It is important not to confuse DLNs with transaction codes.
Both appear on transcripts, but they serve entirely different purposes.
Once assigned, the DLN is:
If your return is pulled for review, the DLN allows the IRS to retrieve the correct digital or physical “folder” instantly.
The IRS Document Locator Number DLN is the IRS’s internal GPS for your tax return.
It tells the IRS:
While most taxpayers never need to act on a DLN, understanding it adds clarity when returns stall or move into manual handling.
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