For those who did not see this post in the Illinois Bowfishers forum...
Robow commented on Lake Mermet where Lady Forge got the nice gar shown above:
I've never seen so many spotted gar before in one location and although I can't say the quantity is there, the average fish is of very decent quality. I shot 6 with the largest going 5 3/4 lbs. I'm sure there are larger and undoubtedly a newstate record spotted gar could be had there since it presently stands at 7+ lbs.
Sounds like it's worth the trip.