A good resource, with all the broods listed, including the two that are going to emerge this year (North Illinois Brood and Great Southern Brood) and the typical ranges of each brood: https://cicadas.uconn.edu/broods/
Just did a search, found this image [1]. It looks like the geographical overlap is a small area in Illinois (light orange and brown regions in linked image).
Here's a better map [1] that shows the overlap better with sample data from the broods, it's an arc from Springfield to about Kankakee, about 120 miles.
[1] https://cdn.britannica.com/32/222432-050-E9798FB1/map-emerge...