Function

• The ABA routing number provides information about what bank a check is drawn from. When given with your account number, it allows a company to debit a bank account electronically.
  
  

Identification

• ABA routing numbers are nine digits long with each digit being a number from 0-9. The routing number has a vertical line followed by a colon on either side.
  
  

Assignment

• Each routing number is unique to a particular bank, though large banks may have more than one routing number for different geographic regions. To receive a new routing number, financial institutions must complete an application through the Official ABA Registrar of Routing Numbers, known as Accuity.
  
  

Features

• The first two numbers of the routing number represent what federal reserve the bank that issued the check reports to. Banks use this information to determine whether a check is local or not, which can effect how quickly funds are available.
  
  

Considerations

• Because the ABA routing number is necessary for the check to be returned to the issuing bank for payment, a check is not valid if the routing number is illegible or missing.