An ABA transit number is the number that is assigned to a particular bank by the American Bankers Association, which is unique to that bank and identifies it. Only financial institutions that are eligible to hold an account at a Federal Reserve bank may be assigned an ABA transit number. Also known as routing numbers, the ABA transit number for a bank is a 9 digit number that may be found on the bottom of any check issued by that bank. In addition to client-centered services such as check clearing, ABA numbers also facilitate the transfer of funds between banks. ABA transit numbers were first issued in 1910 in order to indicate the bank location that the check would eventually be transferred to, but since then they have come to also include other organizations involved in check clearing institutions as well as online banking.