U.S. Bank Routing Numbers: Leading Zeros and ABA Variations Explained

Routing numbers, also known as ABA numbers, are nine‑digit identifiers used by the Automated Clearing House (ACH) network and the Federal Reserve to route electronic payments within the United States. Some institutions issue routing numbers that begin with one or more leading zeros; for example, Wells Fargo’s routing number starts with 000003.

Bank of America, a large national bank, does not rely on a single ABA number. It employs multiple routing numbers that differ by state, region, and transaction type. The correct number is typically printed on checks, shown in online banking portals, or listed on bank statements. Using an incorrect routing number can cause transaction delays, rejections, or lost funds.