US Democratic front-runner Hillary Clinton scored victories over challenger Bernie Sanders in Maryland, Delaware, Connecticut and Pennsylvania.
Her only loss of the night came from Rhode Island, where she still managed to share the delegates with Sanders 11-13.
Hillary’s victory in four other states pushed her delegate count to 2,141, while Sanders has 1,321, including super delegates.
Republican Donald Trump has also extended his lead in his party’s presidential race by winning primaries in Pennsylvania, Maryland and Connecticut.
With 950 delegates in the bag, the controversial businessman from New York, edges closer to seizing the party’s nomination. His nearest rival, Ted Cruz has amassed only 560 delegates.
Victory for Trump in all the five states constitutes a big blow to rivals Ted Cruz and John Kasich, who had forged a Stop-Trump alliance.
Trump, who has gained momentum after losing the Wisconsin primary to Cruz on April 5, was also expected to win the other two Northeastern states that voted, Rhode Island and Delaware.
Cruz was already looking ahead to Indiana’s Republican primary contest on May 3.
“I got good news for you: Tonight, this campaign moves back to more favourable terrain,” the U.S. senator from Texas said in Knightstown, Indiana, inside the high school gymnasium made famous by the underdog movie, “Hoosiers.”
*Story updated at 07.27 a.m with all the results of Super Tuesday