The Illinois Department of Revenue (IDOR) is alerting taxpayers that changes announced by the United States Postal Service (USPS) regarding postmarks 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.
IDOR encourages those taxpayers who mail their returns and tax payments to do so earlier than they typically would to ensure they meet the Wednesday, April 15 filing deadline.
For more information, please see this week’s print edition.