Bank routing numbers, also known as routing transfer numbers, are listed for free on the issuing bank's website. Each bank has a unique routing number that varies by state. A bank's state-specific routing number is also found on checks issued in that state.
Routing transit numbers are nine-digit codes used within the United States facilitate the tracking and transfer of funds from one account to another. The codes were initially created in 1911 to allow banks to transfer and process paper checks. As there were no computer databases, the routing codes served as a type of address that signaled what issuing bank the check came from, and in which state the originating account existed. Over time, the system was expanded to account for new forms of funds transferring.
The largest innovation to funds transfers is the Automated Clearing House protocol. It is a network system that handles credit card and debit card transactions electronically, eliminating the need for paper checks and money orders as proof of a withdrawal or deposit between accounts. The Automated Clearing House system also allows for direct deposit of payroll checks into an employee's account. The system essentially takes the routing number found on checks and converts it into a digital message that is communicated between financial institutions.