Electronic Filing Calendar - IL-1040

Tax Return Liability Period: 01/01/2018 - 12/31/2018
Test transmissions will be accepted:December 21, 2018
Production transmissions will be accepted:January 28, 2019
Last date for timely paid IL-1040 returns:April 15, 2019
Last date to transmit timely filed IL-1040 returns: October 15, 2019
Illinois electronic filing system shuts down:To be determined*
Retention of acknowledgment file materials:December 31, 2019
Retention of electronic return-related materials for non-paid preparers: December 31, 2019
Retention of electronic return-related materials for paid preparers:
(Including original Forms IL-8453 and attachments)
3 years
*Illinois will follow the IRS calendar for shut down.