FIRST INTERSTATE BANK Routing Number 125102430 — BILLINGS, MT

About Routing Number 125102430 — FIRST INTERSTATE BANK

Routing number 125102430 is the official 9-digit ABA routing number registered to FIRST INTERSTATE BANK at P O BOX 30918, BILLINGS, MT 59116-0918. It is registered with the American Bankers Association and the Federal Reserve E-Payments Routing Directory. This number is used exclusively within the US domestic payment system — for ACH transfers, direct deposits, check processing, and domestic wire transfers routed through Fedwire. It cannot be used for international transfers, which require a SWIFT/BIC code.

How to Read Routing Number 125102430

The 9-digit number 125102430 is structured in three segments: 1251 is the Federal Reserve routing symbol — the first two digits identify the Federal Reserve district and the next two identify the specific Federal Reserve processing office handling FIRST INTERSTATE BANK's transactions. 0243 is the ABA institution identifier — four digits assigned by the American Bankers Association uniquely to FIRST INTERSTATE BANK. 0 is the check digit — a single digit calculated from the first eight digits using a weighted sum formula (3-7-1 multipliers). Payment processing systems run this calculation in real time to catch routing number entry errors before any funds move.

ACH, Direct Deposit, and Wire — When to Use 125102430

• Direct Deposit — Payroll and Government Payments: Provide routing number 125102430 and your account number to set up payroll direct deposit, IRS tax refunds, Social Security, VA benefits, or any recurring government payment.
• ACH Transfers — Bill Payments and Bank Transfers: Enter 125102430 when authorising electronic debits or credits — utility bills, insurance premiums, subscription services, or bank-to-bank transfers via NACHA's ACH network.
• Check Payments: This routing number is printed at the bottom-left of every FIRST INTERSTATE BANK personal check in BILLINGS — the first 9-digit sequence in the MICR line.
• Domestic Wire Transfers via Fedwire: Confirm with FIRST INTERSTATE BANK whether 125102430 applies to wires — many banks use a separate wire routing number. Fedwire settles same-day in real time.

What 125102430 Cannot Be Used For

• International wire transfers — require a SWIFT/BIC code. Find FIRST INTERSTATE BANK's SWIFT code at the SWIFT Code Lookup.
• Indian bank transfers (NEFT, RTGS, IMPS, UPI) — require an IFSC code. Use the IFSC Code Lookup.
• Cheque clearing in India — requires a MICR code. Use the MICR Code Lookup.

How to Verify Routing Number 125102430 Is Correct

Before using 125102430 for a large ACH or wire transfer, verify it three ways: (1) Check the bottom-left of a FIRST INTERSTATE BANK personal check — the routing number must match. (2) Log into FIRST INTERSTATE BANK online banking under Account Details. (3) Cross-check against the Federal Reserve routing directory. BankZop sources all routing data from official ABA and Federal Reserve records as of Jun 2026.

Browse more FIRST INTERSTATE BANK routing numbers in MT or across all states. For all US banks, visit the Routing Number Lookup. For international transfers, use the SWIFT Code Lookup. For loan EMI planning, try the EMI Calculator.