By Neta, founder of SortMyDivorce · Published · Updated
90 days in Illinois before the case is filed or before judgment, and no separation period at all, agreed or contested. Illinois does grant legal separation.
Illinois divorce law has its own vocabulary and its own shortcuts — knowing them before you file can save months and a lot of friction.
| Residency requirement | At least one spouse must have lived in Illinois (or been stationed there on military duty) for 90 days before the case is filed, or before a judgment is entered — you can file before hitting 90 days as long as the judgment comes after (750 ILCS 5/401). |
|---|---|
| Grounds | No-fault only: 'irreconcilable differences have caused the irretrievable breakdown of the marriage.' Illinois abolished fault-based grounds (adultery, cruelty, etc.) in 2016. |
| Waiting period | None. Illinois requires no separation period in any case, agreed or contested (750 ILCS 5/401). Living apart for six months or more is not a requirement — it creates an irrebuttable presumption that irreconcilable differences exist, which is a way of proving the ground rather than a wait you must serve. |
| Legal separation | Illinois does grant legal separation. It settles the same questions a divorce settles — support, parenting and, depending on the case, property — but leaves the marriage in place, so neither spouse can remarry without a divorce. |
| If you were never married | Illinois does not create common-law marriage, and living together gives neither partner property or support rights. Claims rest on agreements between you. A common-law marriage validly formed in a state that does create them is generally still recognised. |
| Where you file | The Circuit Court in the Illinois county where you or your spouse resides. Filing in another county requires a motion and court approval. |
| Filing fee | Varies by county — confirm the current amount with your county Circuit Clerk. A fee waiver (Application for Waiver of Court Fees) is available if you cannot afford it. Filing fees are set by the court and change without notice: check the current schedule on the court's own website before you file, and ask about a fee waiver if the cost is a barrier. |
| Starting forms | Petition for Dissolution of Marriage (separate versions for cases with and without minor children), plus Summons or Entry of Appearance and a Financial Affidavit — all available as Illinois Supreme Court Approved Statewide Standardized Forms at illinoiscourts.gov. |
| Simplified option | Joint Simplified Dissolution of Marriage is available only if both spouses agree and meet strict limits (marriage 8 years or less, no children together, no real property, limited retirement assets, combined property under $50,000, combined gross income under $60,000, each spouse's income under $30,000). Illinois does not have common-law marriage, so unmarried cohabiting partners do not go through this dissolution process at all — separating simply requires no court filing unless children or property disputes are involved. |
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Illinois divides property under the Illinois Marriage and Dissolution of Marriage Act (IMDMA), and it is an equitable distribution state, not a community property state. That distinction matters: courts don't start from a 50/50 split. Instead, the court first classifies property as marital or non-marital — generally, what either spouse brought in before the marriage, inherited, or received as a gift stays non-marital — and then divides the marital estate in whatever way it finds fair given factors like each spouse's contributions, economic circumstances, and the duration of the marriage. 'Equitable' does not mean equal, and it's one of the most common misunderstandings people bring into settlement talks.
Illinois also changed its language around children in 2016: you won't see 'custody' in current filings. Instead the law refers to the 'allocation of parental responsibilities' and 'parenting time.' If a letter from the other side's lawyer still uses old terms, that's usually just habit, not a sign of anything strategic — but it's worth knowing the current framework so you can read proposals accurately. Filings go through the Circuit Court in the county where either spouse resides, generally in that court's domestic relations or family division.
Since 2016, irreconcilable differences is the sole ground for divorce in Illinois — you no longer need to allege fault. Built into that ground is a separation requirement: the law generally expects spouses to have lived separate and apart for more than six months before a court will find the marriage irretrievably broken. The practical shortcut most couples use is this: if both spouses agree in writing that irreconcilable differences exist and that efforts at reconciliation have failed, that separation period can be waived. This is the detail behind the common claim that 'Illinois has no waiting period' — it's true specifically when both sides agree, and far less simple when the divorce is contested.
There is also a residency requirement: generally, one spouse must have lived in Illinois for at least 90 days before filing. If you or your spouse recently moved to or from Illinois, confirm this timing early, since it can affect where and when a case can actually be filed.
Illinois divorce cases require each spouse to complete a financial affidavit — a sworn statement of income, expenses, assets, and debts — as part of the mandatory disclosure process. Because it's sworn, accuracy matters more than speed; courts and opposing counsel treat it as a baseline for support and property discussions, and inconsistencies tend to resurface later. Before you're asked to complete one, it helps to have gathered: recent pay stubs and tax returns, retirement and investment account statements, mortgage and property records, credit card and loan statements, and business records if either spouse is self-employed or owns a company.
If any of your property is arguably non-marital — owned before the marriage, inherited, or gifted specifically to you — start collecting the paper trail now (purchase dates, account statements, gift letters). Illinois courts look at tracing evidence closely when a spouse claims something should stay outside the marital estate.
Decisions about parental responsibilities and parenting time in Illinois are made based on the best interests of the child, considering factors like each parent's wishes, the child's needs, and each parent's ability to cooperate on decision-making. Detailed, concrete parenting plan proposals — schedules, holidays, decision-making authority — tend to go more smoothly than vague ones. Child support in Illinois generally follows an income shares model, which looks at both parents' combined income rather than only the paying parent's, so accurate income disclosure from both sides matters for a fair number.
Legal separation is available in Illinois. It is a court proceeding, and in most respects it runs like a divorce: the court can settle support, parenting arrangements and, depending on the case, the division of property, and the resulting order binds both spouses.
What it does not do is end the marriage. People choose it for a range of reasons — health coverage, religious conviction, immigration status, or simply not being ready — and it leaves the door open to reconciling without starting over.
Two consequences follow. Neither spouse can remarry unless they later obtain a divorce, and modifying the order generally takes the court's approval rather than a private agreement between you. If you expect to divorce eventually, ask what converting the separation into a divorce involves here before you start.
Illinois does not create common-law marriage. There is no number of years of living together that turns into a marriage here, and none of the divorce machinery on this page applies to a couple who never married — no property division, no spousal support, no residency requirement to satisfy, because there is nothing to dissolve.
What unmarried partners have instead are ordinary civil claims: whatever you agreed between yourselves, in writing or by clear conduct, and claims over property you actually hold jointly. These are argued like any other contract or property dispute rather than as family-law entitlements, and they turn on what can be proved.
One qualification runs the other way and matters. A common-law marriage validly formed in a state that does create them — Colorado, Iowa, Kansas, Montana, Oklahoma, Rhode Island, Texas or Utah — is generally recognised elsewhere. A couple who met that state's test while living there, and later moved here, are married, and separating means divorcing. Children are unaffected either way: custody and child support are decided on the same basis whether or not the parents married.
1) Confirm both spouses meet Illinois's residency basics before assuming a straightforward filing timeline. 2) Decide early whether you and your spouse can agree on irreconcilable differences in writing — this is the single biggest lever on how long the case takes. 3) Start your financial affidavit documents now, and flag anything you believe is non-marital along with its supporting paper trail. 4) If children are involved, draft a realistic parenting time proposal rather than a vague framework. 5) From the first letter onward, keep a record of every date, deadline, and position — Illinois settlement letters often set response windows, and losing track of one can cost you leverage later. For anything specific to your county's Circuit Court procedures, check that court's official website or confirm with a local family law attorney.
One spouse must have lived in Illinois, or been stationed there in the armed services, for at least 90 days before filing or before the judgment is entered. You can file first and let the 90 days finish while the case is pending.
If you and your spouse agree on everything, you can move straight to an uncontested judgment with no separation period. If you don't agree, the case proceeds as contested, and living apart for 6 continuous months before judgment creates an automatic presumption the marriage is over.
This streamlined track needs mutual agreement, a short marriage (8 years or less), no children, no real estate, and combined property/income under the statutory limits. If eligible, it uses its own set of joint forms and typically resolves faster.
Download the Illinois Supreme Court Approved Statewide Standardized Forms from illinoiscourts.gov — the Petition for Dissolution of Marriage (pick the version with or without minor children), and if children are involved, the Parenting Plan and Allocation of Parental Responsibilities forms.
File in the county where you or your spouse currently resides. Bring the original plus copies as your clerk requires, and pay the filing fee — or file an Application for Waiver of Court Fees if you can't afford it.
If your spouse agrees to the divorce, they can sign an Entry of Appearance. If not, you must have them formally served with a Summons, after which they have 30 days to respond.
Both spouses complete a Financial Affidavit disclosing income, assets, and debts. This is required whether or not the case is contested and forms the basis for dividing property and setting any support.
If you have minor children, you'll need a Parenting Plan and, in some circuits, a required parenting class completed before the final hearing.
Once forms and agreements are complete, the court enters a Judgment for Dissolution of Marriage, which legally ends the marriage and incorporates any settlement or parenting terms.
Not automatically. Illinois is an equitable distribution state, so courts divide marital property in a way they find fair based on factors like contributions and economic circumstances — not necessarily an even split. Confirm how this applies to your situation with a local attorney.
Illinois generally expects a period of living separate and apart before finding a marriage irretrievably broken, but that requirement can typically be waived if both spouses agree in writing that irreconcilable differences exist. Contested cases usually can't skip it.
It's a sworn statement of your income, expenses, assets, and debts, generally required from each spouse in Illinois divorce cases as part of mandatory disclosure. Courts and opposing counsel rely on it, so accuracy matters — check current requirements with your county's Circuit Court or a local attorney.
A legal separation in Illinois settles much of what a divorce settles — support, parenting and, depending on the case, property — and the order binds both spouses. The difference is that it does not end the marriage, so neither spouse can remarry without later obtaining a divorce. People use it for health coverage, religious reasons, immigration status, or because they are not ready to divorce. Changing the order generally requires the court's approval.
No. Illinois does not create common-law marriage, and living together for any length of time gives neither partner property division nor spousal support. Unmarried partners rely instead on agreements between themselves and on claims over jointly held property, argued as ordinary civil matters. One important exception: a common-law marriage validly formed in a state that does create them — such as Colorado, Iowa, Kansas, Montana, Oklahoma, Rhode Island, Texas or Utah — is generally recognised here, so that couple would need a divorce. Custody and child support apply regardless of marriage.
If you are in immediate danger, call 911. For support with domestic violence, contact the Illinois statewide 24/7 hotline at 1-877-863-6338. Nationally you can also reach the National Domestic Violence Hotline at 1-800-799-7233, or text START to 88788 if a call is not safe. For a mental health crisis, call or text 988.
Last reviewed August 2026. Researched and written by Neta, founder of SortMyDivorce. I am not a lawyer and this is not legal advice — laws, fees and forms change, so please confirm current details with the official sources above or a local family lawyer.
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