Illinois per diem rates (FY2026)
Illinois has 4 cities with their own GSA rate. Everywhere else in the state uses the standard rate.
| City / county | Lodging | M&IE |
|---|---|---|
| Bolingbrook / Romeoville / Lemont · Will | $114.00 | $74.00 |
| Chicago · Cook / Lake | $142.00–$234.00 | $92.00 |
| East St. Louis / O'Fallon / Fairview Heights · St. Clair | $150.00 | $86.00 |
| Oak Brook Terrace · DuPage | $115.00 | $80.00 |
About Illinois per diem
GSA has surveyed and listed a non-standard rate for 4 locations in Illinois, topping out at $234.00 a night in Chicago. Every other city or county in the state defaults to the standard CONUS rate of $110.00 lodging and $68.00 M&IE.
On the first and last day of any trip, M&IE is paid at 75% under the first/last-day rule — $51.00 at the standard rate, or the equivalent 75% figure for whichever listed city you're travelling to. See how to calculate per diem for a business trip for the full worked example.
Frequently asked questions
Does every city in Illinois have its own per diem rate?
No — only 4 locations have a separately listed GSA rate in Illinois. Every other city or county in the state uses the standard CONUS rate of $110.00 lodging + $68.00 M&IE.
Which city in Illinois has the highest per diem rate?
Chicago has the highest listed lodging cap in Illinois, at $234.00 a night, compared with $114.00 in Bolingbrook / Romeoville / Lemont.
How do I calculate per diem for a multi-city trip through Illinois?
Use the calculator on each city's page for the nights spent there, then add the totals together — lodging caps and M&IE tiers can differ from one Illinois city to the next, so a single flat rate for the whole trip would be inaccurate.
Calculate a trip → PerDiemWise is an independent tool, not affiliated with the GSA.