What is an ABA Transit Number?

The American Bankers Association (ABA) assigns special numbers to United States banks in order to make check clearing easier. This special number is called an ABA transit number, but is often referred to as an ABA routing number or just a routing number. The ABA assigns these numbers to banks of all sizes. In order to be assigned an ABA transit number, however, a bank has to meet the criteria for Federal Reserve account eligibility.

The ABA transit number originated in 1910 and is currently used for the identification of the bank on which a check is drawn. This number consists of nine digits and is usually found on the bottom line of a check. To find it, a person can look for the first nine numbers listed on the bottom line of a check. It is usually listed to the left of the checking account number.

The ABA transit number that is listed on a check isn't a random number. Each transit number consists of digits that identify the Federal Reserve Bank territory the check is returned to before being presented to the appropriate bank for payment. The nine-digit number also contains digits that are institution identifiers.

People may not have much cause to pay attention to ABA transit numbers when they are writing paper checks. In such a case, there is nothing they have to do with the number. They are often used for making online or phone payments, however. For example, if a person decides to pay his car insurance online or by phone, he is typically asked not only for his checking account numbers and the payment amount he wants to make, but also the ABA transit number. This allows the payment processor to identify the bank from which the funds will be collected.

An individual may need his transit number when the time comes to order new checks for his account. He may also need this number when he wants to arrange a direct deposit to his account or in an automatic withdrawal situation. A person may need to give his ABA transit number when setting up a wire transfer as well.

Interestingly, some banks have more than one ABA transit number. In fact, there are some banks have several different ABA transit numbers, one for each region, as checks from one region may clear through a different Federal Reserve district than those from another region. Larger banks tend to have more than one routing number while smaller banks often have just one.