The National Lottery has released more information on the winner of Saturday's record €19.06m jackpot.
Players in Co Mayo are being encouraged to check their ticket, after one person in Castlebar scooped the jackpot.
The details of the winning shop will officially be revealed on Wednesday.
After more than 60 draws over seven months, the prize was finally won over the weekend.
The winning numbers were 2, 9, 16, 30, 37, 40 and the bonus number was 23.
The Castlebar player has created history by becoming the largest Lotto jackpot winner in the history of the game.
Sarah Orr, spokesperson for the National Lottery, told Newstalk Breakfast they have yet to claim their prize.
"We are hoping to hear from the winner soon - so we would continue advising players in Mayo, or who bought their tickets in Mayo, to make sure to keep checking those tickets.
"It was a QuickPick ticket and the player matched all six numbers.
"We don't reveal the full details of the selling location immediately, this is just to give the winner a bit of time to process the win themselves.
"But I can actually confirm that the winning QuickPick ticket is was bought in Castlebar in Co Mayo".
As the jackpot was capped at €19.06 million, the funds from Saturday's draw that would usually go to the jackpot flowed down to the next highest tier at which there was a winner.
The 'will be won' draw saw 149 winners match five and the bonus - and they will share almost €5.5m, claiming €36,687 each.