The ticket was from Friday's drawing and purchased at the Wawa located at 1860 South Collegeville Road.
The ticket matched all five white balls drawn, 18-58-60-65-67, but not the yellow Mega Ball, 20, to win the $1 million prize.
Lottery officials say the winning ticket holder should sign their tickets and file a claim at the nearest lottery office.
There was no jackpot-winning ticket sold for the October 18 Mega Millions drawing, which boosted the jackpot to $82 million annuity value, or $55.9 million cash. The next Mega Millions drawing will be held on October 22.