Lotto chiefs have revealed that was sold in Enniskerry, Co Wicklow.
The golden ticket was bought at the Texaco Service Station and Spar Express in the town.
However, bosses revealed the lucky winner has still not yet come forward to claim their prize.
A spokeswoman said: "The National Lottery is still encouraging Lotto players in Wicklow and surrounding areas to check their tickets."
Wednesday's life-changing sum was the biggest top prize in nearly two years.
It had been rolling over since June 12 and is the 15th highest in the history of the game in Ireland.
The winning numbers were 10, 13, 23, 24, 25, 44 and bonus number is 12.
And owner of the lucky shop Ken O’Connor claimed he was stunned when he heard the news.
He said: "We just can’t believe it! We heard the news yesterday that the winning ticket was sold in Wicklow but we had no idea it was us until last night, it’s just fantastic.
"The shop is absolutely buzzing this morning and I am just thrilled for our customers and of course our staff.
"Just last year, we sold another winning Lotto ticket worth €5.7 million at another one of our stores in Rathfarnham in Dublin so we’re definitely a lucky retailer for our customers.
"Whoever the winner is, we wish them every bit of luck enjoying this life-changing win."
The jackpot was close to being shared as another Laois player fell one number short, matching five and the bonus ball.
They won €134,412 and bought their ticket in Dunnes Stores at the Kyle Shopping Centre, Portlaoise, Co Laois.
Meanwhile there was no winner of the Lotto Plus 1 top prize of €1million.
The winning numbers were 1, 14, 16, 31, 35, 45 and the bonus was 37.
