How Social Security Numbers are Assigned (2024)

How Are Social Security Numbers Assigned?

This article aims to help you understand how Social Security Numbers are assigned. In 2011, theSocial Security Administration (SSA) changed how they assign Social Security Numbers (SSNs). The new method uses a process called “randomization” to assign SSNs.

The Administration developed a new method to help protect the SSN’s integrity and extend the nine-digit SSN’s longevity (instead of adding additional digits).

SSN Randomization changes the assignment process in several ways. First, it eliminates the geographical importance of the first three digits. Also, the new randomization process eliminates thesignificance of the highest group number.

As a result, the High Group List is frozen in time and can only be used to see the area and group numbers SSA issued before the randomization implementation date.

Overview of Social Security Numbers

A Social Security number is issued to U.S. citizens, permanent residents, and temporary workers in the United States. The number is issued to an individual by the SSA, an agency of the federal government.

Its primary purpose is to track working individuals for taxation purposes and Social Security benefits. Since it was initially introduced, the SSN has become the primary national identification number, even though it was not originally intended to be used as a form of identification.


Since 1972, numbers have been issued by the central office. The first three (3) digits of a person’s social security number are determined by the ZIP Code of the mailing address shown on the application for a social security number.

Previously, before 1972, social security numbers were assigned by SSA field offices. The number merely established that his/her card was issued by one of the SSA offices in that State.


In 2011, the SSA changed the assignment process to a process known as SSN randomization. This process eliminates the geographical significance of the number’s first three digits. Below is an explanation of how the numbers were assigned under the old system that was in effect before 2011.

Social Security Number – Area Group Serial

The Social Security number consists of nine (9) digits, usually written in the format – 1 2 3 – 4 5 – 6 7 8 9. The first three digits of a social security number denote the area (or State) where the original Social Security number application was filed.

Each area’s group number (middle two (2) digits) ranges from 01 to 99 but is not assigned in consecutive order. For administrative reasons, group numbers issued first consist of the ODD numbers from 01 through 09 and then EVEN numbers from 10 through 98, within each area number allocated to a State.

After all numbers in group 98 of a particular area have been issued, the EVEN Groups 02 through 08 are used, followed by ODD Groups 11 through 99.

Within each group, the serial numbers (last four (4) digits) run consecutively from 0001 through 9999.

The chart below shows how Group numbers are assigned:

  • ODD – 01, 03, 05, 07, 09——EVEN – 10 to 98
  • EVEN – 02, 04, 06, 08——ODD – 11 to 99

List of Social Security Number Prefixes for Each State

Following is a list of social security number prefixes for each state. The listing is organized in ascending order based on the SSN prefix, with the corresponding issuing state listed. Remember, these apply only to numbers issued before 2011 under the old system.

SSN Prefix = Issuing State

001-003 = New Hampshire
004-007 = Maine
008-009 = Vermont
010-034 = Massachusetts
035-039 = Rhode Island
040-049 = Connecticut
050-134 = New York
135-158 = New Jersey
159-211 = Pennsylvania
212-220 = Maryland
211-222 = Delaware
223-231 = Virginia
232 = North Carolina
232 = West Virginia
233-236 = West Virginia
237-246 = North Carolina
247-251 = South Carolina
252-260 = Georgia
261-267 = Florida (Also 589-595)
268-302 = Ohio
303-317 = Indiana
318-361 = Illinois
362-386 = Michigan
387-399 = Wisconsin
400-407 = Kentucky
408-415 = Tennessee
416-424 = Alabama
425-428 = Mississippi
429-432 = Arkansas
433-439 = Louisiana
440-448 =Oklahoma
449-467 = Texas
468-477 = Minnesota

478 – 485 = Iowa
486 – 500 = Missouri
501 – 502 = North Dakota
503 – 504 = South Dakota
505 – 508 = Nebraska
509 – 515 = Kansas
516 – 517 = Montana
518 – 519 = Idaho
520 = Wyoming
521 – 524 = Colorado
525 = New Mexico
526 = Arizona
526 = New Mexico
527 = Arizona
528 – 529 = Utah
530 = Nevada
531 – 539 = Washington
540 – 544 = Oregon
545-573 = California
574 = Alaska
575-576 = Hawaii
577-579 = District of Columbia
580 = Virgin Islands
580-584 = Puerto Rico
585 = New Mexico
586 = Guam & American Samoa
586 = All Other Pacific Territories
587-588 = Mississippi
589-595 = Florida (also 261-267)
600-601 = Arizona (designated)
602-626 = California (designated)
700-728 = Railroad Retirement
729-999 = Not used until randomization was introduced.

Note: The number 666 has never been used and will not be used in the future.

Please post a comment below if you are aware of any new number ranges.

SSN Requirements

No law directly requires a natural-born United States citizen to apply for a Social Security number to live or work in the United States. However, some people still live without a number because they view it as a voluntary government program. Those who don’t get a number find it difficult to engage in ordinary acts of commerce or banking activities because they can’t provide an SSN.

Additional Resources

If you want to learn more about the process, visit theSocial Security Administration website. On the website, you can:

  • Get more information on how numbers are assigned and the randomization process
  • Find the offices near you and get directions using the office locator. Just enter your zip code.
  • Learn how to get cards and how to request replacement cards

Questions and Comments

If you have any questions, please post a comment below.

Alright, buckle up for a deep dive into the intricacies of Social Security Number (SSN) assignment. You've stumbled upon a fascinating topic, my friend, and I'm here to break it down for you.

Firstly, kudos to you for delving into the changes made by the Social Security Administration (SSA) in 2011. They switched things up by adopting a process known as SSN randomization. This method was a game-changer, eliminating the geographical significance of the first three digits of an SSN.

In the good old days—pre-2011—the first three digits actually meant something. They denoted the area or state where the SSN application was filed. But, with the advent of randomization, that significance was thrown out the window. No more deciphering someone's origin based on those initial digits.

Now, let's talk about the nitty-gritty of the old system. The SSN, with its nine glorious digits, had a structure: 1 2 3 – 4 5 – 6 7 8 9. The first three were for the area, the next two for the group, and the last four for the serial number. However, the group numbers weren't assigned in a simple, sequential manner. Oh no, there was a method to the madness. ODD numbers from 01 to 09, followed by EVEN numbers from 10 to 98, and then back to ODD and EVEN in a strategic dance.

If you're curious about the prefixes assigned to each state under the old system, I've got your back:

  • 001-003 = New Hampshire
  • 004-007 = Maine
  • 008-009 = Vermont
  • And the list goes on, covering every state with its corresponding prefix.

Now, a little history lesson. Before 1972, SSA field offices were the SSN gatekeepers. The first three digits were tied to the ZIP Code of the mailing address on the application. Post-1972, the central office took charge, and ZIP Codes were no longer the SSN determiners.

Fast forward to the present (well, at least as of my last update in 2022), and there's no law requiring a natural-born U.S. citizen to get an SSN. It's not mandatory, but practically, life without it can be a bit challenging. Try navigating the commerce and banking realms without that magical nine-digit identifier.

If you're hungry for more info, the SSA website is your go-to source. There, you can explore the nitty-gritty of number assignments, the randomization process, find nearby offices, and even learn the art of card acquisition and replacement.

So, my friend, there you have it—a comprehensive breakdown of the intricacies of Social Security Number assignment. Feel free to toss any questions my way!

How Social Security Numbers are Assigned (2024)


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