The anonymous winner now has the choice of taking an $878m pay out in one single transaction, or spreading the total amount over 29 years and receiving payments of $52.7m per year.
The record US jackpot total was set in January 2016, but in that case, three Powerball tickets split a $1.58bn prize.
The jackpot had its single winner but 36 tickets tied for second place in the draw and 419 tickets won the third-place prize.
The accumulating prize was last won by a group of 11 co-workers on 24 July; at that point it had built to $543m.
Mega Millions was created in 2002 and has seen a number of changes to the rules over the years that have reduced the odds of winning, leading to larger jackpots.