An ACH routing number is a 9-digit, unique numeric ID assigned to each banking institution in the ECACH. It’s needed for banks to identify where payments should be taken from and sent to. The routing number is used in conjunction with an account number to send or receive an ACH payment.
But don’t worry, when sending an Electronic Funds Transfer (EFT), you just need to provide the name and 5 digit transit of the receiver’s bank along with their account number. Your bank will figure out the rest.