Either cite case law or actual law.....I think and possibly are not the answers that should be given.
You can go to the Illinois State Police website
Illinois State Police Home Page and click on foid/firearms. Look at the frequently asked questions and you will find...
How can I legally transport a firearm in my vehicle?
1. Unloaded 2. Enclosed in a case, and 3. By persons who have a valid FOID card.
Now #3 is where the NRA lobbyist Todd Vandermyde disagrees. Non residents are not eligible to get a FOID card, therefore he says they can't be required to have one and are exempt from this requirement. The ISP website mentions nothing about carrying it with you when not in a vehicle, the law doesn't say you can't transport on foot, the State Police just don't like the idea.
The State Police website infers that the Unlawful Use of Weapons law says you must transport in a case, it says case shipping box or other container. The Wildlife Code however does require transport to be in a case designed for a firearm. To further muddy the water some communities in the north east part of the state have their own transportation ordinances. Failing to abide by these would be an ordinance violation.
If I wanted a handgun for protection I'd transport it in the console, in a case, unloaded and if stopped I wouldn't consent to a search. I wouldn't need to have it in the case but if a LEO who didn't know about the Diggins decision found it I would be less likely to be arrested. In Southern Illinois you are less likely to have trouble than north east Illinois. You will have to make the choice yourself, just saying what I'd do.
Diggins Case Info:
Link Removed (carrying in the car console)
In a traffic stop you might be asked do you have drugs, guns, or anything illegal in the vehicle. The best answer is "no I have nothing illegal in my vehicle." Next question might be You have nothing to hide so may I search your vehicle? Answer "No you may not" not No I have nothing to hide. Answer No I have nothing to hide and he starts his search, answer yes and he starts his search.
