Illinois Individual Income Tax

Form IL-1040 Illinois Individual Income Tax Return

Form IL-1040 Instructions

More Forms

IL-1040 Due Date
The due date for fi ling your 2011 Form IL-1040 and paying any tax you owe is extended to April 17, 2012.

Who must file an Illinois tax return?

If you were
-an Illinois resident, you must fi le Form IL-1040 if

• you were required to fi le a federal income tax return, or
• you were not required to fi le a federal income tax return, but your Illinois base income from Line 9 is greater than your Illinois exemption allowance.

– Illinois resident who worked in Iowa, Kentucky, Michigan, or Wisconsin, you must file Form IL-1040 and include as Illinois income any compensation you received from an employer in these
states. Compensation paid to Illinois residents working in these states is taxed by Illinois. Based on reciprocal agreements between Illinois and these states, these states do not tax the compensation of Illinois residents.

If your employer in any of these states withheld that state’s tax from your compensation, you may file the correct form with that state to claim a refund. You may not use tax withheld by an employer for these
states as a credit on your Illinois return.

-a retired Illinois resident who filed a federal return, you must fi le Form IL-1040. However, certain types of retirement income (e.g., pension, Social Security, railroad retirement, governmental
deferred compensation) may be subtracted from your Illinois income. For more information, see the instructions for Line 5 and Publication 120, Retirement Income.

-a part-year resident, you must fi le Form IL-1040 and Schedule NR, Nonresident and Part-Year
Resident Computation of Illinois Tax, if

• you earned income from any source while you were a resident,
• you earned income from Illinois sources while you were not a resident, or
• you want a refund of any Illinois Income Tax withheld.

-a nonresident, you must fi le Form IL-1040 and Schedule NR if
you earned enough taxable income from Illinois sources to have a tax liability (i.e., your Illinois base income from Schedule NR, Step 5, Line 46, is greater than your Illinois exemption allowance on Schedule NR, Step 5, Line 50), or you want a refund of any Illinois Income Tax withheld in error. You must attach a letter of explanation from your employer.

Read more about who must file

M. Spik

Editor
25 years of experience managing tax, accounting, payroll, and employment-related information portals. Editor of Accounting Portal since 2011.
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