The filing deadline for Illinois income tax returns has been extended from April 15, 2020, to July 15, 2020. Learn more by clicking here. The Illinois Department of Revenue has established a web page to provide information and resources to help Illinois taxpayers, businesses, and others affected by the coronavirus. For up-to-date information on how Illinois is combatting the Coronavirus outbreak, visit the State of Illinois Coronavirus Response Site. This page will be updated as new information is available. We provide online access to tax forms and printed copies when available. Download and print forms online.