The federal government has broad rules on gun purchases, but states also have various rules on licenses and registration of firearms, as well as limits on how many can be owned by a person.
Additionally, some counties and municipalities have restrictions.
Here's a look at Illinois rules on firearms:
Permit to carry
Illinoisans must receive a Firearm Owner's Identification (FOID) card to own or carry a gun or ammunition. The FOID cards are issued by the Illinois State Police. Applicants are not eligible if they have been convicted of a felony, failed a drug test in the past year and several other disqualifying factors.
In 2013, Illinois became the last state to legalize the concealed carry of loaded weapons in public, following a federal court order to do so. Applying for a concealed carry permit requires 16 hours of firearm training from a state-approved instructor for most people, as well as an electronic of training records.
Where guns are allowed
Illinois law prohibits carrying a firearm in schools, public parks, courthouses, public transportation, anywhere that is licensed to sell alcohol and commercial or charter aircraft.
What types of guns are illegal
Machine guns — defined as a firearm designed to shoot more than one shot with a single pull of the trigger — are illegal to possess in Illinois, matching federal law. The law also prohibits several types of ammunition, including armor piercing bullets.
A FOID card has to be shown when buying a firearm or ammo. The state has mandatory waiting periods of 72 hours for a handgun and 24 hours for a rifle or shotgun.