Having lived and hunted in Illinois also for the past 36 years, I second what Deebz says, and also must add this.....
When it comes to deer hunting in Illinois, DO NOT discount the "corn factor"! The problem with the corn factor, is that you have no possible way of determining what the progress of the corn harvest will be when you get here. In most years, a vast majority of it is already completed by the first week or so of November. But if it's not, then all the moon phases and feng-shui strategies can be knocked into a cocked hat. Fortunatley this doesn't happen all that often. I also like to pay close attention to the amount of acorns that the oak trees are bearing in a particular year. That in and of itself is no deal breaker, but believe me it DOES have an effect, and it can take a year when more corn is still in the fields than you'd like that first week of November and act as a draw on enough does to pull them out of the corn so that you see more buck activity in the woods than you would if there were no reason for them to be there.
In the vast majority of Illinois....and certainly 99% of Illinois where one would pay to hunt....deer are literally within 100 yards or so of tens of THOUSANDS of acres of cornfields at any given time. If they are still standing, and there's not much mast in the woods, then you will have some tough hunting. The more corn that's in the CO-OP and not in the field the better.
The other factor that plays a BIG part...and also which you have no control over or the ability to predict...is what the temperatures will be at that time. The hotter it is, the less visible the activity will be. Note that I said "VISIBLE", because it still will be going on, but just not where and when you will normally see it.
All this said, I can tell you that year in, year out, the time when you will see the most buck activity in the woods is between Halloween and the first week or so of November. Just pray for an early (or on schedule) corn harvest, and cold weather!
Offer No Apologies.....
NRA Endowment Life Member