Imagine scooping a 10-figure payout and having absolutely no idea. For those of us who are super-careful checking our numbers, it's hard to believe anyone could overlook a huge win, but plenty of people have.

Read on for the most colossal unclaimed jackpots of all time. All dollar values are in US dollars, and all jackpot values are those stated at the time without adjustment for inflation. 

One of America's two near-national big jackpot games, Powerball is now offered in 45 states, as well as DC, the US Virgin Islands and Puerto Rico. It holds the world record for the largest lottery prize, a humongous $1.586 billion (£1.4bn), which was shared by winners in three states in 2016. Since the game's launch in 1992, two jackpots have gone partly unclaimed and one totally unclaimed.

Three tickets matched all the numbers for the top prize for the draw on 25 May 2013, bagging three winners in Delaware, Louisiana and Florida a cool  $16.7 million (£10.7m) each. But the person who bought their ticket in the Sunshine State failed to claim by the 180-day deadline and their piece of the pie was redistributed among the participating states and territories.

The California Lottery's flagship in-state game started out in 1986 as SuperLotto, becoming SuperLotto Plus in 2000. Since launching all those years ago, the game has generated a tonne of millionaires. On 11 October 1997, it was set to make an individual or syndicate very rich indeed when the jackpot hit $20 million (£12.2m).

Sadly, nobody claimed the prize within the 180-day deadline set by the California Lottery and the winner, who'd bought the ticket in Moreno Valley, lost out on the life-changing sum of money. On the upside, the forfeited money was channelled into the state's public education system, providing a nice windfall for California's schools.

Three years later, another huge SuperLotto prize went unclaimed. This time around, the winning ticket was sold at a 7-Eleven in West Los Angeles ahead of the 8 January 2000 draw. The store's hardcore lottery regulars searched high and low for the ticket but to no avail.

In fact, the owner of the store believed the ticket was bought by a random passerby who probably forgot they even had it, though one customer interviewed by the LA Times thought the winner had likely died. In any case, the deadline passed and the cash was poured into California's public school system.

Having no clue you've scored the jackpot is bad enough; knowing you've won and not being able to find the ticket has got to be a whole lot worse. This was the fate that befell a hapless woman who claimed she'd bought the winning ticket for California's SuperLotto Plus draw on 14 November 2020 at an ARCO AM/PM store in the Los Angeles suburb of Norwalk.

The day before the 180-day deadline for collecting the $26 million (£20.3m) jackpot was due to pass, the unnamed woman visited the store, telling a member of staff she'd lost the ticket and had a sneaking suspicion she'd left it in a trouser pocket and destroyed it in the wash. Despite CCTV evidence showing the lady buying a ticket, this wasn't enough to back up her claim and the prize was doled out to California's public schools instead.

Yet another SuperLotto Plus jackpot that went unclaimed, the $28.5 million (£17.4m) prize from 10 January 2000 wasn't claimed by the 180-day deadline set by California Lottery authorities. The ticket in question was bought in the San Francisco Bay Area.

More specifically, it was sold two days before the draw at Kavanagh Liquors in San Lorenzo. There's really no way of knowing why the life-changing prize wasn't claimed – perhaps the buyer drunkenly lost the ticket. 

America's other near-national, multi-jurisdictional lottery game, Mega Millions is offered these days in the same states and territories as Powerball, minus Puerto Rico. Three massive Mega Millions jackpots have gone unclaimed during the game's 20-year history, with all three tickets happening to have been purchased in New York.

A ticket sold in the Big Apple borough of Queens on 1 August 2006 matched all six numbers for the draw held that same day, nailing the top prize of $31 million (£16.8m). Mega Millions winners have up to a year to claim, but in this case nobody came forward. Like all unclaimed Mega Millions prizes, the cash was distributed among the states and territories participating in the game.

The Mega Millions jackpot that went unclaimed three years prior was even bigger – the prize money for the draw in question, which took place on 25 April 2003, had rolled over from the previous seven draws, swelling from $10 million (£6.1m) to $46 million (£28.2m). It did however fall way short of the fattest jackpot that year, which stood at $183 million (£112m).

According to lottery officials, the winning ticket was snapped up at the A to Z Grocery & Variety store on Broadway in the Williamsburg neighbourhood of Brooklyn. While the winner was a no-show and didn't land the prize that was rightfully theirs, the convenience store on the other hand was awarded a $10,000 (£6.1k) bonus for selling the ticket, so at least someone ended up happy.

Back to Florida, a $50 million (£30.6m) prize for the state lottery's big-money Lotto game went unclaimed in 2003. The ticket for the 12 March draw was purchased at Kohl's Food Market in North Bay Village, a suburb of Miami. The store owner couldn't recall who he sold the ticket to and said nobody had come in or called to ask about it.

Though it's impossible to know for sure, officials suggested the winner might have been a tourist who simply forgot about the ticket. The biggest unclaimed prize in the state's history, which was subject to a deadline of 180 days, was used for promotions and prizes, bankrolling additional giveaways and ultimately making more money for Florida's public education system, which the lottery was set up to support.

The other Powerball jackpot to go partly unclaimed totalled $103.5 million (£69.1m), with the winning numbers drawn on 14 September 2002. Incidentally, at the time only 23 states plus DC and the US Virgin Islands were participating in the game. The states did include Indiana, where one of the two winning tickets was bought.

The ticket was purchased at a Crystal Flash gas station close to Indianapolis International Airport, perhaps by a jet-lagged motorist heading home after a vacation or business trip, which would go some way towards explaining why it was overlooked. Whatever the reason, the 180-day deadline passed with no sign of the winner and their cut of the jackpot – $51.8 million (£34.6m) – went back to the participating states and territories.

The biggest unclaimed jackpot in California state lottery history stands at $63 million (£41.2m). The winning ticket was bought on 8 August 2015 at a 7-Eleven in the Los Angeles suburb of Chatsworth. With the six-month deadline imminent, officials were getting ready to distribute the cash to California's schools when a claimant came out of the woodwork.

Brandy Milliner filed a lawsuit alleging he'd attempted to turn in the "winning" ticket only for lottery officials to reject it due to its horrendous state, though there were no records he'd tried to make a claim. Having performed a forensic examination of the illegible ticket, lottery officials discerned from the paper stock used that it was bought at a different 7-Eleven on a different date. The judge concurred and Milliner's claim was unceremoniously thrown out.

The largest unclaimed Mega Millions jackpot to date also sparked a legal drama. The sole winner of the top $68 million (£45.4m) prize drawn on Christmas Eve 2002 failed to collect the money by the 12-month deadline, but at the 11th hour Brooklyn resident Dr Fritzner Bechette filed a lawsuit against the New York Lottery, claiming the prize.

Bechette, who had lost his ticket, argued he'd been trying to claim the prize with no success. As it turned out, his description of the ticket and place of purchase didn't add up. The actual winning ticket, which was purchased at the Kings Plaza Newsstand in Brooklyn, never materialised and Bechette's claim came to nothing. Needless to say, the money was eventually handed back to the participating state and territory lotteries.

The biggest unclaimed Powerball prize of all time totalled a hefty $77.1 million (£48.1m). The sole ticket matching all five numbers plus the Powerball was bought on 29 June 2011, the day of the draw, at the Pilot Travel Center in Tallapoosa, Georgia, not far from the Alabama state line.

The whereabouts of the ticket and its owner have remained a mystery as nobody emerged to claim the prize before or after the 180-day deadline. Unlike the Mega Millions and SuperLotto Plus cases we've just highlighted, there were no legal challenges and the cash was quietly redistributed among the states and territories involved.

Nine European nations take part in the big-stakes EuroMillions game. Since its launch in 2004, only one major jackpot has gone unclaimed –well, half of it to be precise. Two tickets, one bought in Belgium and the other in the UK, matched all seven numbers picked for the draw on 8 June 2012, with each winner landing a payout of $101 million (£63.8m).

The Belgian winner wasted no time collecting their prize, but the buyer of the UK ticket, who purchased it in the Stevenage or Hitchin area of England, failed to come forward, missing the 180-day deadline. On a positive note, the money was funnelled into the UK National Lottery's Good Causes fund to benefit charities, trusts and associations across the UK.

The jackpot for Japan's Mega Big lottery, which is run by the country's Sport Council, comes in at a whopping 1.2 billion yen – equivalent to $166 million (£120.8m) at the time of this unclaimed prize. The 1,221st draw took place on 8 February 2021 without a glitch but, in contrast to the previous ones, the holder of the winning ticket was nowhere to be found. The clock began ticking on a 12-month deadline.

A flurry of publicity just before the deadline was set to elapse didn't appear to help, and the ticket, which was purchased at a Lawson convenience store in the southern Japanese seaside city of Saiki, was never claimed. Instead, the money was paid to Japan's Treasury and used to promote sport in the country.

Not all lottery winners have missed out. Here are some who have won the jackpot more than once