The relevant law is at 720 ILCS 5/33A-1 to 720 ILCS 5/33A-3
https://www.ilga.gov/legislation/ilcs/ilcs5.asp?ActID=2100&ChapterID=59
Definitions and Penalties:
- The Illinois Domestic Violence Act of 1986 was written in a deliberate manner so as to make construal of its meanings broader and more open-ended than is usually the case in state criminal statutes. Judges are instructed to apply the penalties for such crimes as and assault, battery, abuse, harassment, and unlawful detaining. You can get charged with domestic violence just for shouting or pointing a finger too close to someone with whom you share a domicile.
- Unless aggravating factors are present, domestic violence usually gets prosecuted as a Class A misdemeanor. If you are convicted of a Class A misdemeanor in Illinois, you may get a sentence of up to 364 days in jail (with two years of probation possible instead), and a fine of up to $2,500.
- If, however, aggravating factors are present, domestic battery may be charged as a Class 4 Felony with possible penalties of one to three years of imprisonment (three to six years of incarceration if it is an extended sentence) and a fine of up to $25,000. Thirty months of probation may be available.
- Aggravating factors include battering, any use of a weapon (especially a firearm), any act done against a child or a senior or someone with a disability, or any assault sexual in nature. It is also the case that any prior conviction for domestic battery will probably result in a Class 4 felony charge. You may be ordered to attend anger management classes or psychological counseling. Court ordered orders of protection may be issued if abuse or potential abuse has been deemed probable and breaking such an order is a Class A misdemeanor