The biggest halftime lead in Super Bowl history is 25 points.
In Super Bowl XXI, the Redskins led the Broncos 35-10 at the half. In fact, Washington scored 35 points in the second quarter. That still is good for the most points scored in a single quarter in Super Bowl history.
Washington won the game, 42-10.
Biggest Comeback in Super Bowl History
The biggest comeback in Super Bowl history is the Patriots' 25-point comeback against the Atlanta Falcons in Super Bowl LI.