The winning numbers were 16, 21, 30, 35, 65 plus the gold Mega Ball 7.
The jackpot was an estimated $533 million with a cash option of $244.2 million.
The winning ticket was purchased online.
Mega Millions said Illinois has won or shared in 17 jackpot wins over the years.
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Tickets are sold in 45 states, Washington, D.C., and the U.S. Virgin Islands. Tickets are $5 each and include a randomly assigned multiplier, multiplying the base prize levels by 2X, 3X, 4X, 5X or 10X.
The odds of winning the jackpot are 1 in 290,472,336.