Per Diem Rates for Multi-City Trips

A multi-city itinerary can cross rate boundaries, fiscal-year periods, and lodging locations. For federal CONUS travel, GSA's Per Diem Rates page states that reimbursement is based on the location of work activities, not accommodations, unless lodging is unavailable at the work activity and the agency may authorize the rate where lodging is obtained. This is a federal locality principle, not a universal formula for every private travel policy. The procedure below creates a day-by-day record and flags cases that require agency interpretation.

Build a dated itinerary by work locality

Create one row per travel date with the work location or locations, scheduled activity, overnight location, and whether lodging was available near the work activity. Use the work destination—not automatically the hotel, airport, or city of departure—to identify the relevant GSA locality. Confirm the NSA boundary or standard CONUS status, and check the rate lookup for the date and fiscal-year period. A trip crossing a date-specific rate period should retain each period's lookup result rather than carrying one rate across the entire itinerary.

Do not choose a higher rate simply because it appears in another city on the itinerary, average two cities, or combine lodging and M&IE amounts. GSA FAQ #16 says the federal rules do not provide for “mixing and matching” lodging and M&IE rates. The rate page also says the accommodation locality may be authorized when lodging is unavailable at the work activity; this is an exception to the stated work-location basis, not a blanket convenience choice. Record the unavailability and obtain the agency authorization required for the case.

Worked example: consecutive work locations

Suppose, hypothetically, a federal traveler performs work in City Cedar on Monday and City Bay on Tuesday, while the rate lookup lists different M&IE and lodging amounts for the two localities. The traveler stays overnight in City Bay on Monday because no lodging is available near the City Cedar work site. The reviewer records Monday's work locality, the lodging constraint, the Tuesday work locality, and the date-specific GSA lookup results. If the agency authorizes use of the lodging locality for Monday, preserve that authorization; do not assume that Monday's full daily treatment switches automatically to City Bay. All city names and example rates are illustrative, not current data.

Escalate days that span more than one locality

GSA's published page establishes the work-activity basis and the unavailable-lodging exception, but it does not provide a universal arithmetic split for every day that includes work in two localities. If a traveler begins work in one city and finishes in another, retain the timeline and ask the agency travel office which locality and authorization procedure govern that date. Do not prorate by hours, use the highest rate, or switch at a city boundary unless agency guidance directs that method. The same care applies when an itinerary changes after approval.

For a trip that includes Alaska, Hawaii, U.S. territories or possessions, or a foreign country, GSA's main rates page directs travelers to DoD or State Department rate sources rather than the CONUS table. Private organizations should consult their own written travel policy for multi-city allocation and not import federal locality rules by default. For unresolved federal questions, keep the claim pending with a clear note instead of silently selecting a favorable rate.

Checklist for a reviewable calculation

1. Map each date to work locations, overnight location, and itinerary changes.
2. Verify locality boundaries and date-specific GSA rates for each relevant work location.
3. Document unavailable lodging and obtain agency authorization before using the lodging locality.
4. Ask the travel office to resolve same-day multi-locality treatment; retain its decision with the claim.