The largest lottery jackpot in US history - a whopping $656 million - will be shared by the buyers of three winning Mega Millions tickets in Illinois, Kansas and Maryland - but their identities remained a mystery, lottery officials said.

A pre-dawn call alerted Denise Metzger, manager of a Motomart convenience store, to news from lottery officials that her store had sold a winning ticket in the tiny farming community of Red Bud in southern Illinois, with less than 4,000 residents, about 30 miles (48 km) southeast of St. Louis.

"I screamed, I woke my husband up," said Metzger, whose retail outlet will receive $500,000 for selling a winning ticket.

The Mega Millions lottery created a stir across the country, with people rushing to buy the $1 tickets in time for a shot at the humongous jackpot. In all, more than a billion tickets were sold.

At least two of the winners' tickets were "quick picks" - meaning all six numbers of the Mega Millions lottery computer selected the lucky numbers announced at the drawing Friday night in Atlanta: 2-4-23-38-46 and Mega Ball 23.

Lottery officials said winning tickets were purchased at a 7-Eleven store in Milford Mill, Maryland, near Baltimore, and the Motomart convenience store in Red Bud. The Kansas Lottery said a winning ticket was sold in the most populated northeastern part of the state but did not give the precise location.

Winners could receive either a one-time payment of their share or take it in 26 annual installment payments.

The three tickets each were worth more than $213 million before taxes, if the payout was over 26 years. If taken in a lump sum, the windfall would be about $105.1 million, officials said.

"Each of the winners gets $105.1 million in cash after taxes roughly, but who cares about pennies at this point?" said Carole Everett, spokeswoman for the Maryland Lottery.

No matter who wins the jackpot, one certain winner is the U.S. Internal Revenue Service. The tax-collecting agency subjects lottery winnings of more than $5,000 to a 25-percent federal withholding tax.

'Everyone in town'

Metzger said residents swarmed the store within hours of the announcement to check their tickets, although no winner had yet emerged, she said.

"I think everyone in town has been here already," she joked.

Though that winner - who had not yet contacted Illinois lottery officials - may want to remain anonymous, in Illinois the state is required to eventually list his or her identity in public records.

The winning Maryland ticket was a single quick-pick ticket sold on Friday at the 7-Eleven franchise in Milford Mill, Everett said.

"They are shocked they are getting the $100,000 bonus," Everett said of Ethiopian immigrants Abera and Mimi Tessema, who have owned the 7-Eleven for 10 years and learned they would get a winning seller's bonus.

In addition to the three jackpot winners, there were three tickets that matched the Mega Ball number to win $1 million each and 158 tickets that picked five of the six chosen numbers to win $250,000 each, said Kelly Cripe, spokeswoman for the Texas Lottery, which oversaw the Mega Millions game.

The previous largest Mega Millions jackpot was $390 million in 2007, which was split between two ticket holders in Georgia and New Jersey.

About half the lottery money goes back to ticket holders in the form of winnings, 35 per cent to state governments and 15 percent to retailer commissions and lottery operating expenses. – Reuters