ABA Bank Routing Transit 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 assigned to each banking or financial institution. The American Bankers Association (ABA) initially designed the numbering system in 1910 to facilitate the processing of paper checks.

Since then, the ABA has begun 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 at the bottom of a personal or business check.

Who Assigns Routing Numbers?

Accuity, a SourceMedia company, is the registrar responsible for assigning new ABA numbers. They publish the list of ABA routing numbers in the American Bankers Association Key to Routing Numbers semi-annually. 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 must be in the 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 1985, but now the numbers may be used by any bank, although credit unions primarily use them. For example, this range of numbers correlates to the Federal Reserve Banks as follows:

  • 21 = Boston, Massachusetts
  • 22 = New York, New York
  • 23 = Philadelphia, Pennsylvania
  • 24 = Cleveland, Ohio
  • 25 = Richmond, Virginia
  • 26 = Atlanta, Georgia
  • 27 = Chicago, Illinois
  • 28 = St. Louis, Missouri
  • 29 = Minneapolis, Minnesota
  • 30 = Kansas City, Missouri
  • 31 = Dallas, Texas
  • 32 = San Francisco, California

The numbers 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 for traveler’s checks.

How to decode the Third and Fourth digits

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

How to decode the Fifth through the Eighth digits

Next, the fifth through eighth digits are the ABA Institution Identifier. The institution identifier 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 digit. Check sorting equipment verifies the checksum. If the checksum fails, the item routes to a “reject pocket.” The reject pocket is where someone manually examines the check. Then, they make repairs and resubmit for sorting.

What do private investigators need to know?

Private detectives who conduct financial investigations, perform forensic accounting, and run asset searches should clearly understand these numbers to facilitate decoding financial transactions, tracing payments, and finding assets.

Questions and Comments

Please leave a message below if you have questions about the ABA bank routing number. Also, here are some resources for more information:

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


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