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TaxSlayer Pro Knowledgebase Illinois Articles
Illinois Forms and Instructions
Individual Corporation S Corporation Partnership Fiduciary Nonprofit
E-file Info ● General Tax Return Info ● Filing Status Info ● Residency Info ● Military ● Reciprocity
Business ● Nonprofits ● Mailing Addresses ● Business Mailing Addresses ● Federal Links
Electronic Filing Information
Electronic Filing Mandate - If an income tax return preparer prepares more than 10 individual income tax returns those returns must be filed using electronic technology.
An “opt out” declaration form (Form IL-8948) must be retained by the preparer in the event the taxpayer elects to not electronically file their tax return. The Form IL-8948 should not be mailed with the paper return and is only submitted by a preparer upon request. The preparer should retain in their records any completed Form IL-8948 for three years.
Click here for a fillable PDF copy of Form IL-8948.
E-File Registration Requirements - Acceptance in the Illinois e-file program is automatic with acceptance in the federal e-file program.
Tax Years That Can Be E-Filed – Current year and 2 prior years
State Only Return Requirements – Illinois supports transmission of returns to the IRS as linked (federal and state) or unlinked (state-only or standalone) returns.
Amended Returns - Electronically filing the Illinois amended return is supported for tax years 2022 and forward. For years prior to 2022 taxpayers must file a paper return and mail it to the appropriate address. (See Mailing Addresses below).
Electronic Signatures – Illinois does not currently support electronic signatures on their tax forms.
General Tax Return Information
Due Date - Individual Returns - April 15, or the same as the IRS
Extensions - Illinois allows an automatic extension to October 15 without filing a form. If the taxpayer receives a federal extension of more than six months, the taxpayer is automatically allowed that extension for Illinois. To make an extension payment, use Form IL-505-I, Automatic Extension Payment for Individuals. Form IL-505-I must be mailed with payment to the appropriate address (See Mailing Addresses below).
Driver’s License/Government Issued Photo Identification - Illinois does not require this information to file the tax return.
Filing Status Information
Note: TaxSlayer Pro does not support a different filing status on the Illinois return.
Illinois requires the same filing status used on the federal return except in the following situations.
- If a joint federal return is filed and there is an injured spouse, file MFS in Illinois. Each spouse determines income and exemptions as if they had filed separate federal returns. Election must be made by the extended due date of the return, and once a filing status is chosen, it is irrevocable for the tax year.
- If a joint federal return is filed, and one spouse is a full-year resident while the other is a part-year resident or nonresident, taxpayers may elect to file MFS in Illinois. Do not recompute any items on the federal return. Instead divide each item of income and deduction shown on the joint federal return between the separate Illinois returns following the Allocation Worksheet in the instructions. If an MFJ Illinois return is filed, both spouses are treated as residents. This election is irrevocable for the tax year. Credit is allowed for income tax paid to another state.
Residency Status Information for Illinois Returns
Residents: Individuals domiciled in Illinois for the entire tax year. Domicile is the place where a person resides and the place where he or she intends to return after temporary absences. Temporary absences may include duty in the Armed Forces, residence in a foreign country, or out-of-state residence as a student or during the winter or summer. A person absent from Illinois for one year or more is presumed to be a nonresident.
Part-year resident: Individuals who move into or out of Illinois during the year. Part-year residents must file Form IL-1040 and Schedule NR, Nonresident and Part-Year Resident Computation of Illinois Tax, if they earned income from any source while they were a resident, they earned income from Illinois sources while they were not a resident, or they want a refund of any Illinois Income Tax withheld.
Nonresidents: Individuals who are domiciled outside Illinois. Nonresidents must file Form IL-1040 and Schedule NR if they earned enough taxable income from Illinois sources to have a tax liability (i.e., Illinois base income from Schedule NR, Step 5, Line 46, is greater than Illinois exemption allowance on Schedule NR, Step 5, Line 50), or they want a refund of any Illinois Income Tax withheld in error. A letter of explanation from your employer must be attached to the return. If a taxpayer is a nonresident and their only income in Illinois is from one or more partnerships, S corporations, or trusts that withheld enough Illinois Income Tax to pay their liability, they are not required to file a Form IL-1040.
Military Personnel/Military Spouses
Residents and nonresidents required to file in Illinois may be able to subtract qualifying military pay on line 7, Form IL-1040.
Residents: Residence does not change solely by reason of assignment to duty in another state. If domiciled in Illinois at the time of joining the Armed Forces, or elected to change residence to Illinois after being stationed there, the taxpayer remains an Illinois resident for tax purposes unless they elect to become a resident of another state.
Nonresidents: Service members domiciled in other states and stationed in Illinois on a temporary basis are nonresidents. Nonresidents must file if they earn enough taxable income from Illinois sources to have a tax liability. Military pay is not taxable income.
Military spouses: Under the Military Spouses Residency Relief Act, a spouse’s state of residence does not change when he or she moves to a new state because the service member is stationed in the new state.
Reciprocal Agreements
Residents of Iowa, Kentucky, Michigan, and Wisconsin are required to file an Illinois return only if they received Illinois-source income other than compensation for services or want a refund of Illinois taxes withheld.
Compensation paid to an Illinois resident working in these reciprocal states is taxed by Illinois, and they must report all compensation received on Form IL-1040. Based on reciprocal agreements, these states do not tax the compensation of Illinois residents. If an employer in a reciprocal state withheld that state’s tax, an Illinois resident may file with that state to claim a refund. An Illinois resident may not use tax withheld by an employer for these states as a credit on his or her Illinois return.
Business Return Electronic Filing Information
Business Electronic Filing Mandate - If an income tax return preparer prepares 25 or more acceptable, original corporate/partnership income tax returns using tax preparation software in a calendar year, then for that calendar year and for each subsequent calendar year thereafter, all acceptable corporate/partnership income tax returns prepared by that income tax preparer must be filed using electronic technology.
Business Return General Information
Due Dates for Illinois Business Returns
Corporations - April 15, or same as IRS
S-Corporations - March 15, or same as IRS
Partnerships - March 15, or same as IRS
Fiduciary & Estate - April 15, or same as IRS
Business Extensions
Corporation - An automatic six-month extension of time to file is granted until 6 months after the original due date of the return. This automatic extension does not extend the payment of any tax due. If the C Corporation expects tax to be due, it must use Form IL-505-B to pay any tentative tax due in order to avoid interest and penalty on tax not paid by the original due date of the return. An extension of time to file the Illinois C Corporation Income Tax Return, Form IL-1120 is not an extension of time for payment of Illinois tax.
If the C Corporation will be filing the return on extension but needs to make a payment by the original due date, this payment can be made online at MyTax Illinois or can be submitted by mail on Form IL-505-B Automatic Extension Payment. To access the Automatic Extension Payment Voucher, from the main menu of the Illinois Corporation return select Miscellaneous Forms and Schedules > IL Form IL-505-B-Extension Payments. Enter the amount of the payment to be made as an extension payment and mail it to the address on the form.
S-Corporation - An automatic seven-month extension of time to file is granted until 7 months after the original due date of the return. This automatic extension does not extend the payment of any tax due. If the S-Corporation expects tax to be due, it must use Form IL-505-B to pay any tentative tax due in order to avoid interest and penalty on tax not paid by the original due date of the return. An extension of time to file the Illinois S-Corporation Income Tax Return, Form IL-1120-ST is not an extension of time for payment of Illinois tax.
If the S-Corporation will be filing the return on extension but needs to make a payment by the original due date, this payment can be made online at MyTax Illinois or can be submitted by mail on Form IL-505-B Automatic Extension Payment. To access the Automatic Extension Payment Voucher, from the main menu of the Illinois S-Corporation return select Total Payments > Form IL-505-B. Enter the amount of the payment to be made as an extension payment and mail it to the address on the form.
Partnership - An automatic six-month extension of time to file is granted until 6 months after the original due date of the return. This automatic extension does not extend the payment of any tax due. If the Partnership expects tax to be due, it must use Form IL-505-B to pay any tentative tax due in order to avoid interest and penalty on tax not paid by the original due date of the return. An extension of time to file the Illinois Partnership Income Tax Return, Form IL-1065 is not an extension of time for payment of Illinois tax.
If the Partnership will be filing the return on extension but needs to make a payment by the original due date, this payment can be made online at MyTax Illinois or can be submitted by mail on Form IL-505-B Automatic Extension Payment. To access the Automatic Extension Payment Voucher, from the main menu of the Illinois Partnership return, select Total Payments > Form IL-505-B. Enter the amount of the payment to be made as an extension payment and mail it to the address on the form.
Fiduciary - An automatic six-month extension of time to file is granted until 6 months after the original due date of the return. The extension doesn't have to be requested. This automatic extension does not extend the payment of any tax due. If the Fiduciary expects tax to be due, it can pay online or by mail.
If the Fiduciary will be filing the return on extension but needs to make a payment by the original due date, this payment can be made online at MyTax Illinois or can be submitted by mail on Form IL-1041-V. To access the Automatic Extension Payment Voucher, from the main menu of the Illinois Fiduciary return select Amount of Overpayment to be Refunded > Total Payments > Credits and payments made before the original tax due date > Extension Payment. Enter the amount of the payment to be made as an extension payment and mail it to the address on the form.
Amended Business Returns
Illinois Amended Business Returns cannot be e-filed.
Corporation - Business taxpayers must complete Form IL-1120-X and mail it to the mailing address on the form. To complete Form IL-1120-X, from the main menu of the Illinois return, select IL-1120-X Amended Return.
S Corporation - Business taxpayers must complete Form IL-1120-ST-X and mail it to the mailing address on the form. To complete Form IL-1120-ST-X, from the main menu of the Illinois return, select IL-1120-X Amended Return.
Partnership - Business taxpayers must complete Form IL-1065-X and mail it to the mailing address on the form. To complete Form IL-1065-X, from the main menu of the Illinois return, select IL-1065-X Amended Return.
Fiduciary / Estate - Business taxpayers must complete Form IL-1041-X and mail it to the mailing address on the form. To complete Form IL-1041-X, from the main menu of the Illinois return, select IL-1041-X Amended Return.
Exempt Organizations
An organization that resides in or is qualified to do business in Illinois that is exempt from federal income tax under IRC section 501(a) and is filing federal Form 990-T must also file Form IL-990-T to the state of Illinois, due on or before the 15th day of the 5th month following the close of the organization's tax year.
The organization needs to be registered with the Illinois DOR. This can be done at MyTax Illinois or by mailing a completed copy of Form REG-1, Illinois Business Registration Application to the Illinois DOR.
TaxSlayer Pro does not support Form IL-990-T. Click the Nonprofit link above to get the form and instructions at the Illinois DOR website.
Mailing Addresses
Individual Income Tax Mailing Addresses
| No tax due, or balance due no payment |
Balance Due with payment | Payment Voucher Only |
| Illinois Department of Revenue PO Box 19041 Springfield, IL 62794-9041 |
Illinois Department of Revenue PO Box 19027 Springfield, IL 62794-9027 |
Illinois Department of Revenue Springfield, IL 62726-0001 |
Business Mailing Addresses
Corporate Income Tax Mailing Addresses
| Paper returns without payment | Paper returns with payment |
| Illinois Department of Revenue PO Box 19048 Springfield, IL 62794-9048 |
Illinois Department of Revenue PO Box 19038 Springfield, IL 62794-9038 |
S Corporation Income Tax Mailing Addresses
| Paper returns without payment | Paper returns with payment |
| Illinois Department of Revenue PO Box 19032 Springfield, IL 62794-9032 |
Illinois Department of Revenue PO Box 19053 Springfield, IL 62794-9053 |
Partnership Income Tax Mailing Addresses
| Paper returns without payment | Paper returns with payment |
| Illinois Department of Revenue PO Box 19031 Springfield, IL 62794-9031 |
Illinois Department of Revenue PO Box 19053 Springfield, IL 62794-9053 |
Fiduciary Income Tax Mailing Addresses
| Paper returns without payment | Paper returns with payment |
| Illinois Department of Revenue PO Box 19009 Springfield, IL 62794-9009 |
Illinois Department of Revenue PO Box 19053 Springfield, IL 62794-9053 |
Federal Tax Links
e-Services for Tax Professionals
Disclaimer
While TaxSlayer Pro strives to make the information and links contained on this page as timely and accurate as possible, TaxSlayer Pro makes no promise or guarantee about the timeliness, accuracy or completeness of the contents of this page. The information contained on this page is for general information and is not intended to be tax advice. The user is also encouraged to review the underlying state resources and publications.