Indiana Code Title 6. Taxation § 6-3-4-3

Sec. 3. (a) Returns required to be made pursuant to section 1 of this chapter shall be filed with the department on or before the later of the following:

(b) If the due date for a federal income tax return is extended by the Internal Revenue Service to a date that is later than the date specified in subsection (a)(1) or (a)(2) (as applicable), the department may extend the due date of a return required to be made under section 1 of this chapter to reflect the due date permitted for the federal income tax return.

(c) If the due date for a federal income tax return in the Internal Revenue Code, as determined without regard to any extensions, Saturdays, Sundays, or holidays recognized by the Internal Revenue Service, is later than the date provided in subsection (a), the due date for the return made pursuant to section 1 of this chapter shall be the later of the due date for the federal income tax return or the due date provided under this section.