Most regionals this year were 9 teams. Of those, 47 runners (out of a possible 63) advanced- 6 teams of 7, and the 5 highest placing individuals not on a qualifying team. At one of the regionals, two teams tied for 6th. Ties are normally broken in cross-country, but the IHSA's rules say if two teams have the same numerical score, they both advance. So 54 runners (7 teams, 5 individuals) advanced from that regional.
Before the late 1960's (1969, I think), the IHSA only had one elimination meet before State, and that was the Sectional. The numbers of schools fielding cross-country teams continued to grow, so they added the regional meets to keep the Sectional fields manageable. Then they split into two classes. Then three. Now, at least in 2A and 3A, there are fewer schools in the class than there were running single class cross-country in the mid 1960's.
The issue for cross-country is the availability of courses that can handle large fields. A cross-country course requires a long, open starting area, and if park districts have such areas they often turn them into soccer fields. More needs to be done to develop permanent courses in places that will never be otherwise developed- like forest preserves- to ensure the long term health of a sport for which Illinois is among the nation's best states.
The IHSA advisory committee has, over the last couple of years, at least advanced the possibility of eliminating the Regional level, but mostly because they are having more trouble finding schools to host the meet, mostly because the costs of running a regional meet (chip timing and scoring, venue charges) exceed what the IHSA is willing to reimburse the school for hosting the meet.
Back to the football discussion...