A crowd of 15,427 people packed the Grandstand to see the headliner.
That broke an Illinois State Fair record, set by Jason Aldean in 2011, by almost 100 people.
SEE MORE: Democrats rally at Illinois State Fair days ahead of DNC in Chicago
Lil Wayne was part of a list of performers that includes Smashing Pumpkins, Keith Urban and Motley Crue.
The Smashing Pumpkins will headline on Friday on the Grandstand. The show starts at 8 p.m. and doors open an hour earlier.
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The Illinois State Fair runs through Sunday.