Aha, the map server is fixed so we can now see the December snowfall maps (below). The heaviest snowfall totals were in northern Illinois and far southern Illinois and in the 10 to 15 inch range. Snowfall was slightly less across central Illinois. All of Illinois was above-average on snowfall (second map) for December. The highest departures were in southern Illinois at 6 to 10 inches, since December snowfall is typically much less in that region.
By the way, you can see snowfall maps for Illinois, updated daily, at http://www.isws.illinois.edu/atmos/statecli/Current/current.htm
Also, you can make your own maps by setting up a free account on the Midwestern Regional Climate Center cli-MATE service at http://mrcc.isws.illinois.edu/CLIMATE/