This was the location of the RC Motorplex race track. By my best recollection, this 270 feet long paved oval track for radio-controlled car racing was built in the late 1980's. It is located next to Lily Lake in McHenry County. Lights were installed for night racing. A nearby building to the west of the track had a small R/C parts shop and an indoor dirt off-road track.
One of my favorite races on the outdoor track involved a 500 lap race for 1/10 scale cars. It was my only race which involved pit stops for fresh battery packs and tires. The mosquitoes were out in full force, and my racing focus was tested by the thirsty bugs.
If anyone coming across this page can provide more information (track history, etc.), please leave a comment below.