Every Illinois divorce follows the same statutory skeleton: petition, disclosure, discovery, resolution. What separates a smooth case from a punishing one is how each stage is handled. This guide walks through the process under the Illinois Marriage and Dissolution of Marriage Act, from the first filing to the final judgment.
Grounds and Residency Requirements in Illinois
Illinois is a pure no-fault state. The only ground for divorce is irreconcilable differences. Fault concepts like adultery and abandonment were removed from the statute in 2016, and living separate and apart for six months creates an irrebuttable presumption that the standard is met. "Separate and apart" does not require separate homes, either. Spouses can satisfy it while living under one roof, which matters for families weighing the cost of a second household during the case.
Jurisdiction requires that at least one spouse has resided in Illinois for 90 days before the judgment. Filing typically happens in the county where either spouse lives. For Chicago, that means the Domestic Relations Division of the Circuit Court of Cook County.
Filing the Petition, and Whether It Matters Who Files First
The case begins when one spouse files a petition for dissolution of marriage and serves the other with a summons. The responding spouse generally has 30 days to appear and respond. If the respondent never appears, the court can eventually enter a default judgment on the petitioner’s terms, which is why ignoring a summons is the one unambiguous mistake in this process.
Filing first carries no legal advantage in Illinois. The petitioner gains no presumption and no head start with the judge. It can carry practical advantages, though: you choose the timing, you frame the initial requests for temporary relief, and you begin the case prepared instead of reacting to it.
Cook County also imposes an automatic dissolution stay once the case is filed and served. Both parties are restrained from concealing or dissipating assets and from removing minor children from the state without consent or court order. The stay exists to freeze the playing field while the case proceeds.
Financial Disclosure and Discovery in an Illinois Divorce
Early in the case, both parties exchange a court-form financial affidavit disclosing income, expenses, assets, and debts, supported by documents like tax returns and account statements. The affidavit is signed under penalty of perjury, and courts take material omissions seriously.
In contested and high-asset matters, formal discovery follows: interrogatories, document requests, depositions, and subpoenas under the Illinois Supreme Court Rules. This is where complex estates are actually won or lost. Our separate guide on discovery in an Illinois divorce covers the tools and the strategy in depth.
Temporary Relief While the Case Is Pending
Divorces take time, and life continues during them. Under Section 501, either party may ask the court for temporary orders covering maintenance, child support, parenting time, exclusive possession of the home, and interim attorney fees. A separate provision allows courts to level the playing field on fees so that the spouse who controls the money cannot simply outspend the other.
Temporary orders deserve more respect than they usually get. They set the tone of the case, and an unfavorable temporary structure has a way of becoming the template for the final one. We prepare for these hearings the way we prepare for trial.
Children: Parenting Plans and Allocation Judgments
Where minor children are involved, Illinois requires each parent to file a proposed parenting plan, typically within 120 days of the case beginning. If the parents agree, the court reviews and enters the plan. If they do not, the court allocates parenting time and significant decision-making under the best-interests factors, often with input from a guardian ad litem or child representative.
Cook County also requires divorcing parents to complete a parenting education program before judgment. It is a modest requirement, but an unfinished class is a common and avoidable reason final judgments get delayed.
Settlement, Trial, and the Judgment of Dissolution
Most Illinois divorces resolve by a negotiated marital settlement agreement covering property, support, and, where applicable, an allocation judgment for the children. Cases that cannot be settled proceed through pretrial conferences, where the judge often signals how contested issues would likely be decided, and then to trial before a judge. Illinois does not use juries in dissolution cases.
The judgment of dissolution incorporates the agreements or the court’s rulings and legally ends the marriage. Even in a fully agreed case, at least one brief court appearance, called a prove-up, is typically required. Many counties, including Cook, allow these to be done remotely.
How Long a Divorce Takes in Illinois
An uncontested divorce with full agreement can conclude within weeks of filing. Contested matters commonly run six months to more than a year, and complex estates longer, driven mostly by discovery and valuation disputes rather than court backlog. Preparation shortens the arc. The side that arrives with a complete, documented picture of the estate controls the pace, because it gives the other side fewer reasons to delay and stronger incentives to resolve.