The jackpot had been $586 million, but lottery officials increased it Tuesday morning because of strong ticket sales ahead of the evening drawing.
The jackpot now trails only a $656 million Mega Millions pot in March 2012.
Mega Millions changed its rules in October to help increase the jackpots by lowering the odds of winning the top prize to about 1 in 259 million.
Paula Otto, lead director for Mega Millions, says officials expect about 70 percent of the possible number combinations to be purchased. The cash option is $341 million, before taxes.
Mega Millions is played in 43 states, the District of Columbia and the U.S. Virgin Islands.