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News – Tuesday, January 27, 2026
FY 2026-17, Changes to United States Postal Service on Postmarks Could Impact Illinois Tax Filings
The United States Postal Service (USPS) has announced changes to postmarks that could impact tax filings in 2026. While the USPS postmark will still show the date of the first automated processing operation, the postmark may no longer reflect the date when the piece of mail was dropped off at a local post office. This change can directly impact time-sensitive documents such as tax returns and payments.
See Informational Bulletin FY 2026-17, Changes to United States Postal Service on Postmarks Could Impact Illinois Tax Filings for more information.