ABA Bank Routing Transit Numbers

Bank Routing Numbers
Learn about ABA bank routing numbers.

An Overview of ABA Routing Transit Numbers

A bank routing number, also known as a Routing Transit Number (RTN) or an ABA Routing Number, is a unique nine-digit number that is assigned to each banking or financial institution. The numbering system was originally designed by the American Bankers Association (ABA) in 1910 to facilitate the processing of paper checks.

Since that time, the ABA began partnering with registrars to manage the system. Today, the code is used by Automated Clearing Houses (ACH) to process direct deposits, bill payments and other automated transfers. The ABA routing number is usually found at the bottom of a personal or business check.

Who Assigns ABA Bank Routing Numbers?

Accuity, a SourceMedia company, is the registrar that is responsible for assigning new ABA numbers. They publish the list of ABA routing numbers in the American Bankers Association Key to Routing Numbers semi-annual publication. Currently, there are approximately 30,000 numbers currently in use.

How to decode the First Two Digits

The first two digits of the nine digit ABA Routing Number correspond to the 12 Federal Reserve Banks. The first two digits of the nine digit ABA number must be in the ranges 00 through 12, 21 through 32, 61 through 72, or 80.

01 through 12 are the “normal” routing numbers and correlate to the Federal Reserve Banks as follows:

  • 01 = Boston
  • 02 = New York
  • 03 = Philadelphia
  • 04 = Cleveland
  • 05 = Richmond
  • 06 = Atlanta
  • 07 = Chicago
  • 08 = St. Louis
  • 09 = Minneapolis
  • 10 = Kansas City
  • 11 = Dallas
  • 12 = San Francisco

The numbers 21 through 32 were assigned only to thrift institutions through the year 1985, but now the numbers may be used by any bank, although they are primarily used by credit unions. This range of numbers correlates to the Federal Reserve Banks as follows:

  • 21 = Boston
  • 22 = New York
  • 23 = Philadelphia
  • 24 = Cleveland
  • 25 = Richmond
  • 26 = Atlanta
  • 27 = Chicago
  • 28 = St. Louis
  • 29 = Minneapolis
  • 30 = Kansas City
  • 31 = Dallas
  • 32 San Francisco

The number 61 through 72 are used for electronic transactions by non-bank processors. The numbers correlate as follows:

  • 61 = Boston
  • 62 = New York
  • 63 = Philadelphia
  • 64 = Cleveland
  • 65 = Richmond
  • 66 = Atlanta
  • 67 = Chicago
  • 68 = St. Louis
  • 69 = Minneapolis
  • 70 = Kansas City
  • 71 = Dallas
  • 72 = San Francisco

The number 80 is used for traveler’s checks.

How to decode the Third and Fourth digits

The third digit corresponds to the Federal Reserve check processing center that was originally assigned to the bank. The fourth digit is 0 if the bank is located in the Federal Reserve city. If not, it 1–9 depending on which state in the Federal Reserve district it is in.

How to decode the Fifth through the Eighth digits

The fifth through eighth digits are known as the ABA Institution Identifier and represents the bank’s unique ABA identity within the Federal Reserve district.

How to decode the Ninth digit

The ninth, check digit is a checksum test that uses a position-weighted sum of each of the digits. Check sorting equipment verifies the checksum. If the checksum fails, the item is routed to something known as a “reject pocket”, where it is then manually examined, repaired if necessary, and then resubmitted for sorting.

What do private investigators need to know?

Private detectives who conduct financial investigations, perform forensic accounting and run asset searches should have a clear understanding of these numbers to facilitate decoding financial transactions, tracing payments, and finding assets.

Following are resources for more information:

  • ABA Routing Numbers– The official ABA site provides detailed Information on the background and development of ABA routing numbers, how to obtain an official number and much more. Run a routing number search. Companies who need access to the entire Routing Number database or who may be applying for a routing number should contact Accuity, the Official Registrar.
  • Financial Products and Services – An overview of various financial products and services.

If you have any questions about bank routing numbers, please leave a message below.


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