ABA routing numbers

According to ACAMS International Glossary of Key Money Laundering Terms and Acronyms, ABA routing numbers refer to nine-digit numbers assigned to all U.S. banks that are used to identify a bank for purposes of domestic wire transfers. Each routing number begins with two digits corresponding to the bank’s Federal Reserve District (e.g., '01' for the New England area, '02' for New York, '11' for Texas, etc.), followed by two digits denoting the city, state, or region within that district. These are followed by four digits unique to that bank. The routing number ends with a digit that is the 'algorithmic key', which ensures the integrity of the number.