For those that don’t already know, a routing number is a nine-digit number that is used to identify a bank or financial institution within the United States. This is an essential piece of information to hold when you are trying to clear funds or making an online transfer. It is also used to process checks. Clearinghouses will rely on the routing number to accurately process financial transactions. Without routing numbers, online banking would simply be unable to function. Not every financial institution will have a routing number, but most will. It is only the federally chartered and state chartered banks that will be eligible to maintain an account at a Federal Reserve Bank that is issued routing numbers. Routing numbers have been used for more than a century, as they were first established by the American Bankers Association in 1910. Routing numbers are essential when it comes to setting up a wire transfer. There is no physical currency that moves between banks through this type of transfer, only the information is transmitted from one bank to the other. This is why a transaction must go through without any problems to have the correct routing number. Routing numbers are also used in direct deposits of money from employers that are paying employees. As well as this, they can be used for income tax refunds from the Internal Revenue Service.  Interestingly, routing numbers are not always referred to as routing numbers, and they do sometimes go by other names. There are a few other terms that are used by the industry for the same 9 digit number.  You will usually find that routing numbers are often also could routing transit numbers, or even ABA numbers. ABA is an acronym for the American Bankers Association, and this is the organization that established routing numbers back in 1910, so it makes sense for it to be called this.