US Banking
ABA Routing Transit Number
An ABA routing number (also called a routing transit number or RTN) is a nine-digit code that identifies a US financial institution. Originally created in 1910 by the American Bankers Association, routing numbers are used to direct ACH payments, Fedwire transfers, and check processing to the correct bank.
The first four digits encode the Federal Reserve routing symbol, which indicates the Federal Reserve district and processing center. The next four digits identify the specific institution, and the ninth digit is a checksum calculated using a weighted modulus-10 algorithm. For example, in 021000021 (JPMorgan Chase), the leading 02 indicates the New York Federal Reserve district. You can validate any routing number using BankCheck.
Routing numbers are essential for nearly every type of US payment. An incorrect routing number can cause payments to be rejected or sent to the wrong bank. Large banks may have multiple routing numbers for different states or purposes (ACH vs. wire), so verifying the correct one before sending a payment prevents delays and returned transactions.
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