A nine-digit number, also known as the bank routing number or ABA number, which is used within the banking system to identify a financial institution. The number is used on items (checks, ACH transactions, etc.) that belong to a specific financial institution so that they can be routed through the banking system to the proper institution.  You can find your ABA number by looking at the bottom left of one of your checks from your checkbook.  Faxless payday loans typically require that you provide your ABA number on your loan application so that two things can happen: 

1. The payday lender can deposit your faxless payday loan into your bank account; and
2. The payday lender can debit (or withdraw) your faxless payday loan fees and repayment from your bank account.

To fully identify your bank account to the payday lender, you need to provide BOTH your ABA number and your account number.