 TITLE: Routing Number vs. Account Number: What’s the Difference? CONTENT: A routing number is a nine-digit number that identifies the bank or credit union where an account is held. These numbers are also commonly referred to as ABA routing numbers, referring to the American Bankers Association, which assigns them.\nRouting numbers are only used within the U.S. and show that the financial institution has an account with the Federal Reserve and is chartered at either the federal or state level.\nIn most cases, banks and credit unions only have one routing number. But some large national and multinational banks may have multiple routing numbers based on where you live or hold the account. END