A routing number, a crucial component of check processing, identifies the financial institution that handles the account the check is drawn upon. For instance, a routing number of 123456789 would indicate that the check is associated with bank number 123456789.
Routing numbers streamline the processing of financial transactions and ensure checks are directed to the appropriate banks. Historically, routing numbers in the U.S. evolved from the nine-digit American Bankers Association (ABA) routing transit number, which later became the MICR (Magnetic Ink Character Recognition) routing number.