Look at the bottom left corner of your checks. The first nine-digit number on the left is the bank routing number. Immediately to the right of that is your checking account number.
The account number can also be found on the signature card which was given to you at the time your account was opened.
You may also contact your local branch to ask for your account number. You can find the phone number to your branch here.
Please note, your account number is not the same as your debit card number.