10K races are not spread evenly across December. Here is how the calendar actually falls, weekend by weekend, which is the part worth knowing before you book a trip or plan a taper around one.
Dec 5 - Dec 61
Dec 12 - Dec 133
Dec 19 - Dec 201
Dec 26 - Dec 273
By the numbers
The Biggest Field
The largest field of any December 10K in Illinois, from the most recent published results.
Common Questions About Running a December 10K in Illinois
When in December are most 10K races held?
The busiest weekend in Illinois is December 12 and December 13, with 3 of them. One more falls on a weekday, which is worth knowing if you are traveling for it.