How many digits are in an ABA routing number?

An ABA routing number, also known as a bank routing number or a routing transit number (RTN), consists of 9 digits. This unique identification number is used to identify financial institutions in the United States, especially for the processing of checks and electronic funds transfers. The format is specifically designed so that the first two digits indicate the Federal Reserve district and the following digits identify the specific bank. Understanding the structure of the ABA routing number is crucial for bank tellers, as it ensures accurate processing of transactions and helps prevent errors in fund transfers. This foundational knowledge is essential in providing efficient banking services.