How to File for Divorce in Illinois: Residency, Grounds & Waiting Period

In Illinois, you (or your spouse) must have lived in the state — or been stationed there while on military duty — for at least 90 days before a judgment of dissolution can be entered. Illinois is a no-fault state: the only ground for divorce is "irreconcilable differences," and if both spouses agree the divorce is appropriate, there is no separation period or waiting period required to prove that ground. If you don't agree, living separate and apart for a continuous 6 months immediately before the judgment is entered creates an irrebuttable presumption that irreconcilable differences exist. The case is filed in Circuit Court and is formally called a "Dissolution of Marriage."

The 90-day residency requirement

Illinois law requires that at least one spouse have maintained residence in Illinois — or, for military members, have been stationed in Illinois — for 90 days before the case begins or before the court makes its residency finding. A judgment of dissolution cannot be entered until this 90-day threshold is satisfied. If you've recently moved to Illinois, this is a real timing issue: filing before you hit the 90-day mark can hold up your case, so confirm your specific dates with the Circuit Clerk's office where you plan to file.

Grounds: irreconcilable differences is the only ground

Illinois abolished fault-based divorce effective January 1, 2016. You cannot file for divorce in Illinois based on adultery, cruelty, abandonment, or similar fault grounds anymore. The sole ground available is irreconcilable differences — meaning the court must find that irreconcilable differences have caused the irretrievable breakdown of the marriage, and that efforts at reconciliation have failed or that further attempts at reconciliation would be impracticable.

The waiting period: when 6 months of separation matters — and when it doesn't

This is one of the most misunderstood parts of Illinois divorce law:

• If you and your spouse have lived separate and apart for a continuous period of at least 6 months immediately before the judgment is entered, Illinois law treats that as conclusive (irrebuttable) proof that irreconcilable differences exist. You don't have to argue about the "why."
• If you have not been separated for 6 months, that's not necessarily a barrier — the statute also says that if both spouses agree the marriage should end, no separation period and no waiting period is required to establish grounds.

In practice, this means an uncontested divorce where both spouses agree can often move faster than a contested one where the parties disagree about whether the marriage should end.

Is there a faster, simplified option?

Time-sensitive — verify current numbers before relying on this: Illinois offers a Joint Simplified Dissolution procedure for couples who meet a specific set of statutory limits, including:

• A marriage of no more than 8 years;
• No children born or adopted of the marriage, and no pregnancy;
• No ownership of real estate;
• Marital property and income below certain statutory thresholds; and
• Both spouses waiving maintenance (alimony).

The dollar and income thresholds for this simplified track are set by statute and have been adjusted over time, so the current figures are not reproduced here — confirm the up-to-date numbers with your county's Circuit Clerk or the court's self-help resources before assuming you qualify. If your situation doesn't fit these limits, you'll use the standard dissolution process instead.

Where and how a divorce is filed

Divorce cases in Illinois are filed in the Circuit Court, generally in the county where you or your spouse lives, and the case type is officially titled a "Dissolution of Marriage." The Illinois Supreme Court Commission on Access to Justice has approved statewide standardized forms covering divorce, child support, and maintenance (spousal support), which all Illinois courts are required to accept. Using the approved statewide forms — rather than a form you found elsewhere — helps avoid rejected filings.

Property division basics

Illinois divides property under a "marital property" framework. By statute, marital property means essentially all property — including debts and other obligations — acquired by either spouse during the marriage, with specific exceptions that are treated as "non-marital property." Those exceptions include (among others):

• Property acquired by gift, legacy, or descent (or property acquired in exchange for such property);
• Property acquired in exchange for property owned before the marriage;
• Property acquired by a spouse after a judgment of legal separation; and
• Property excluded by a valid agreement between the parties, such as a premarital or postnuptial agreement.

How marital property and debt actually get divided in your case depends on the full circumstances of the marriage — this is a general framework, not a formula, so don't assume a strict 50/50 split.

If children are involved

Illinois law refers to custody-type decisions as the "allocation of parental responsibilities," decided in an "allocation judgment." The statute defines "caretaking functions" broadly — covering things like a child's nutritional needs, bedtime and wake-up routines, care during illness or injury, hygiene, and similar day-to-day tasks — as part of how courts and parents describe who does what for a child. If domestic abuse is part of your case, Illinois law points to the definition of "abuse" used in the Illinois Domestic Violence Act of 1986 as the controlling definition.

Military spouses: two federal protections to know

If you or your spouse is on active military duty, two federal laws can affect your Illinois case:

• Servicemembers Civil Relief Act (SCRA): A servicemember whose military duties materially affect their ability to appear in court can obtain a stay of at least 90 days in a civil case, including divorce, custody, and support proceedings. This protects deployed or active-duty parents and spouses from default judgments entered while they can't participate.
• Uniformed Services Former Spouses' Protection Act (USFSPA): This federal law allows Illinois courts to treat a servicemember's "disposable retired pay" as marital property that can be divided in the divorce. Direct payment of a former spouse's share through the Defense Finance and Accounting Service is only available if the couple was married 10 or more years overlapping 10 or more years of military service (the "10/10 rule"). USFSPA does not create an automatic 50/50 entitlement — how much, if anything, a former spouse receives is still decided under Illinois property-division law.

What you can do in Illinois

1. Confirm residency timing. Make sure you or your spouse will have met the 90-day Illinois residency (or military stationing) requirement by the time you expect a judgment to be entered.
2. Decide whether you agree on ending the marriage. If both spouses agree, you may not need to wait out a separation period. If you don't agree, track your separation date — 6 continuous months immediately before judgment satisfies the grounds requirement.
3. Check whether the Joint Simplified Dissolution track fits. Review the marriage-length, no-children, no-real-estate, and income/property limits, and confirm current dollar thresholds with your Circuit Clerk.
4. Get the correct statewide forms. Use the Illinois Courts' approved statewide standardized Divorce, Child Support, and Maintenance forms rather than an unofficial template.
5. File in the right Circuit Court — generally the county where you or your spouse live.
6. If a servicemember is involved, note whether an SCRA stay request or USFSPA 10/10-rule issue applies to your timeline or property division.

Time-sensitive items to double-check before you file: the current Joint Simplified Dissolution dollar/income thresholds, and your exact residency start date relative to your intended filing or judgment date. Both are the kind of details that change or that a few days can affect.

This article is general information about Illinois law, not legal advice for your situation — confirm current details with your Circuit Clerk or an Illinois attorney.