In Illinois, you can base your divorce on either fault or no-fault grounds as the basis for seeking a divorce, or you can base your divorce on the fact that you've been separated from your spouse for at least 24 months. The reason you might want to use fault grounds is to gain an advantage in a contested child custody case or a dispute about the division of marital property or the appropriateness or amount of alimony. To learn more about whether Illinois uses fault as a determining factor in child custody, alimony, and property issues, see Nolo's Essential Guide to Divorce, by Emily Doskow.
At least one spouse must be a resident of Illinois for three months or 90 days before filing for divorce.
Illinois is an equitable division state. In an equitable division state, each spouse owns the income he or she earns during the marriage, and also has the right to manage any property that's in his or her name alone. But at divorce, whose name is on what property isn't the only deciding factor. Instead, the judge will divide marital property in a way that the judge considers fair, but won't necessarily be exactly equal.
Like all states, Illinois courts begin with a presumption that it's best for a child to have frequent and continuing contact with both parents after a divorce. If possible, judges want to support joint custody arrangements. However, the exact nature of the time-share will be determined by the children's best interests. For more information, see Nolo's article Child Custody FAQ.
Like all states, Illinois requires both parents to support their children, even after a divorce. The amount of child support depends primarily on each parent's income and other resources, and how much time each parent spends with the children. In addition, sometimes the courts will "impute" income to a parent who has the capacity to earn more than he or she actually is earning. To learn more about child support, see Nolo's Child Support area.
Yes. You can usually get fill-in-the-blank forms at your local courthouse or the local law library. And you can go to this online resource for Illinois, where you'll find extensive information about do-it-yourself divorce, along with court forms (in some states).