The Powerball jackpot has risen to $334 million, the 12th largest in the game's history.
No one won the jackpot on Wednesday, and the next drawing is set for Saturday. The lump-sum cash prize for the winner is $205 million.
Iowa Lottery spokesman Kevin Kirkpatrick says the prize hasn't been this large since March 2013, when a New Jersey man won $338 million.
Powerball's largest jackpot was more than $590 million in May 2013. Kirkpatrick says the game would have to continue a few more rounds without a winner before it could reach that level.
The odds of winning the Powerball jackpot are 1 in 292 million.