Lottery officials in Georgia identified the winner as Ira Curry, of Stone Mountain, which is east of Atlanta. Curry will take a lump sum of $123 million after taxes, Georgia Lottery chief executive Debbie Alford said.
"She has not decided how she'll spend those winnings," Alford said at a news conference that Curry did not attend.
The other winning ticket was sold at a gift shop in San Jose, Calif. There winner there has one year to come forward.
Curry was driving to work Wednesday when a radio announcer talked about the Mega Ball being No. 7. Curry knew that was her Mega Ball number, so she called her daughter to check the ticket.
"Between joyful tears and laughter on the daughter's part, she relayed to her mother that her mother had won the lottery," Alford said.
Alford wouldn't say where Curry worked or how old she was. A person who answered the phone at a listing for Curry said, "We are not interested in any publicity, thank you for calling" and then hung up.
Curry, her husband and other family members came to the lottery headquarters to claim the prize, surprising lottery officials who thought the winner may take some time to get their affairs in order before coming forward.
Alford said she didn't think Curry believed she had won until lottery officials told her congratulations.
"She said she was just in a state of disbelief," Alford said.
The winning ticket in Georgia was sold at a newsstand in Buckhead, a financial center of Atlanta about 10 miles from Stone Mountain Park. The park features a 825-feet-tall mountain that covers about 1-square mile. There are golf courses, camping, bike and walking trails there as well as a carving depicting Confederate heroes of the Civil War, including Gen. Robert E. Lee.
Curry's house is just a few miles from the park. A man who answered the door at her home in a suburban neighborhood of brick and stucco houses with manicured lawns also said the family did not want to speak. The two-story home had a two-car garage and a basketball hoop.
The ticket was sold at the Gateway Newsstand in the Alliance Center building, which is home to a variety of offices, including lawyers, financial services professionals and even the Brazilian Consulate General.
The newsstand is a small, narrow shop with one register. It can hold about 10 people at a time and it is located near the lobby.
Young Soo Lee owns the store with her husband, Young Lee. She grinned as she arrived Wednesday morning.
"I'm so excited and so happy now," Young Soo Lee said. "I love my store and the customer."
Earlier media reports indicated the couple would receive a bonus for selling a winning ticket, but Georgia Lottery spokeswoman Tandi Reddick clarified that's not the case.
"They do have the distinction of being known as the lucky store now, and that's always great news for them," Reddick said.
The California store owner — Thuy Nguyen of Jennifer's Gift Shop in San Jose — will get $1 million, lottery officials there said.
Nguyen told KNTV he doesn't know who the bought the winning ticket at his store, which sits along San Jose's tree-lined Tully Road, amid a cluster of Asian restaurants. But it's likely someone he knows because most of his customers are his friends.
"I feel good! I don't even know, I can't sleep," Nguyen told the station.
The winning numbers were 8, 14, 17, 20, 39 and Mega Ball 7.
The jackpot started its ascent Oct. 4. Twenty-two draws came and went without winners.
Some $336 million in tickets were sold for Tuesday's drawing.
Mega Millions changed its rules in October to help increase the jackpots by lowering the odds of winning the top prize. That means the chances of winning the jackpot are now about 1 in 259 million. It used to be about 1 in 176 million, nearly the same odds of winning a Powerball jackpot.
Associated Press writers Christina A. Cassidy, Phillip Lucas and Jeff Martin in Atlanta, and Sudhin Thanawala in San Francisco, contributed to this report.
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