Illinois Divorce Laws

Overview: Divorce in Illinois

Illinois's 2016 Marriage and Dissolution of Marriage Act brought sweeping modernization to the state's family law. The elimination of fault grounds, adoption of a maintenance formula, and new "parental responsibilities" framework make Illinois one of the most forward-looking family law jurisdictions.

Whether you are considering filing for divorce, navigating a custody dispute, or evaluating your options for spousal support, understanding Illinois's specific laws is the essential first step. This guide covers the key legal requirements and rules that apply to divorces filed in Illinois.

Residency Requirements

At least one spouse must have been an Illinois resident for at least 90 days before filing.

Filing before the residency requirement is met will result in the court dismissing your petition. If you have recently moved to Illinois or are considering which state to file in, confirming residency eligibility is the critical first step. An experienced Illinois family law attorney can confirm whether you currently qualify to file.

Grounds for Divorce in Illinois

Illinois eliminated all fault-based divorce grounds in 2016. The state is now a pure no-fault jurisdiction. The only ground is irreconcilable differences, established by either mutual agreement or 6 months of separation.

For most divorcing couples, no-fault divorce is the most practical choice — it avoids the time and cost of proving marital fault in court. However, in states where fault can influence financial outcomes, discussing grounds strategy with your attorney before filing is worthwhile.

Property Division in Illinois

Illinois divides marital property equitably using a multi-factor analysis that considers each spouse's economic circumstances, contributions to the marital estate (including homemaker contributions), and the duration of the marriage. Only marital property is subject to division; non-marital property remains separate.

Marital property generally includes assets and debts acquired during the marriage, while separate property (owned before marriage, or received as a gift or inheritance) is typically excluded. Complex assets like retirement accounts, business interests, and real estate often require professional valuation and careful legal handling.

Waiting Periods & Timeline

Illinois has no mandatory waiting period. However, no-fault divorce using "irreconcilable differences" requires either mutual agreement or a 6-month period of living separate and apart.

Even in states without a mandatory waiting period, the practical timeline for divorce — from filing to final decree — typically ranges from 60 days for simple uncontested cases to 12–24 months for contested divorces. Contested issues like property valuation, business interests, or custody disputes can extend timelines significantly.

Child Custody in Illinois

Following 2016 reforms, Illinois replaced the terms "custody" and "visitation" with "parental responsibilities" and "parenting time." Courts allocate significant and routine decision-making responsibilities and parenting time based on the best interests of the child.

Child custody decisions are not permanent — they can be modified after the initial order if there is a substantial change in circumstances. Courts in Illinois will always prioritize the best interests of the child over the preferences of either parent.

Types of Custody

• Legal custody — the right to make major decisions about the child's education, healthcare, and religious upbringing
• Physical custody — where the child primarily lives
• Joint custody — both parents share legal and/or physical custody
• Sole custody — one parent has primary legal and/or physical custody

Alimony & Spousal Support in Illinois

Illinois calls spousal support "maintenance." The state uses a statutory formula: maintenance = (33.3% of payor's net income) minus (25% of payee's net income). Duration is based on the length of the marriage. Courts may deviate from the formula in complex cases.

Alimony is not automatically awarded in Illinois and is not available in every divorce. The requesting spouse must demonstrate financial need, and the court must find that the other spouse has the ability to pay. If you believe you may be entitled to spousal support — or may be required to pay it — consulting with a Illinois family law attorney early in the process is important.

What Makes Illinois Divorce Law Distinctive

Illinois completely overhauled its family law system in 2016, eliminating fault divorce entirely and replacing traditional custody language with a modern "parental responsibilities" framework focused on children's outcomes.

Frequently Asked Questions: Divorce in Illinois