If someone hits the jackpot, it will be the 10th largest prize in US lottery history.
The Mega Millions draw on Friday night is worth $450m (£332m) which is its fourth-largest jackpot in history.
Almost one billion dollars is up for grabs on two lottery drawings this weekend.
The latest increase to the jackpot would be the fifth largest in Powerball history if someone matched all six numbers Saturday night.
Together they constitute the third-largest ever jackpot combined total.
Long odds have not stopped "lottery fever" from spreading, with people lining up at retailers to buy the $2 tickets, said Jeff Lenard, spokesman for the National Association of Convenience Stores, whose members sell about 60 percent of the nation's lottery tickets.
All day on Friday, the manager at the Sun Fresh Supermarket near Mill Street and Southwest Trafficway in Westport says the line at his customer service counter was buzzing around the clock.More news: Some Android games are spying on your TV habits through your microphone
Americans spent $80.5 billion on lottery games a year ago, according to the North American Association of State and Provincial Lotteries.
Both games are played in 44 states plus Washington, D.C., and the U.S. Virgin Islands. Mega Millions tickets are offered in the same locations excluding Puerto Rico. The biggest Mega Millions jackpot was in 2012, when three winners split $656 million.
Tickets for each drawing can be purchased up until one hour before drawing.
The estimated totals are before taxes are assessed.
Last time someone won the Mega Millions jackpot was October 13 and the Powerball last saw a victor October 25.