A routing number is also called routing transit number (RTN). It is a nine digit bank code, used in the United States, which checks the financial institution on which it was drawn.
This code helps to facilitate the sorting, bundling, and shipment of paper checks back to the drawer's (check writer's) account. Most common types of transaction being ACH and wire transfers. Some banks and credit unions may have multiple routing numbers serving different purposes, geographical regions or branches.
Routing numbers are printed on the bottom of a check. They can also be found on online banking sites of the financial institution. The Routing number is also used by Federal Reserve Banks to process Fedwire funds transfers,
and by the Automated Clearing House to process direct deposits, bill payments, and other such automated transfers.