Once the prize is claimed, the retailer where the ticket was bought will receive $50,000.
The winning ticket's numbers matched all six numbers drawn (5-28-62-65-70, and Megaball 5).
SC is one of eight states where winners can remain anonymous.
One extremely lucky person overcame 302.5 million to one odds last month to win Mega Millions' record $1.5 billion jackpot.
The mystery ticketholder who matched all six numbers in the October 23 drawing has 180 days from to come forward.
Lottery officials confirmed that a ticket purchased at the KC Mart #7 on Lee Vaughn Road in Simpsonville matched all six numbers in the October 23 drawing.
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"They still have over 100 days to come forward", Holli Armstrong, a South Carolina Education Lottery spokeswoman, told CNN on Wednesday.
There is a 180-day deadline - until April 21 - to cash in the ticket.
If the jackpot goes unclaimed, each participating state will get back all the money it contributed.
There were several other big winners who fell one number short of the jackpot as well.
The lucky victor can choose to receive a lump sum of $878 million or $1.537 billion in installments over 30 years.
"Our message to the $1.5 BILLION #Mega Millions jackpot victor: Sign the back of the ticket, place the ticket in a safe location, speak with a trusted advisor and CALL THE LOTTERY at 1-866-736-9819".
One Twitter user had a suggestion about what to do with the money in the event the victor never steps forward: "Why doesn't the gov't just pick 25k lotto winners 1.5B/26K=$60K each and save itself the hassle?"