The ticket was bought in Fife, Scotland, on July 23. The £1 million prize, and all the interest it has earned, has now been passed on to the UK National Lottery Good Causes.
A National Lottery representative said, "We tried very hard to find the ticket-holder and it's a real shame that they have missed out."
Eight raffle winners from the July 26 draw have just two days left lose their to claim their £1 million prizes.
Anyone who thinks they may hold a winning ticket for any of the National Lottery draws should call the National Lottery Line on 0845 910 0000.