Democratic Barack Obama and Republican John McCain beat their opponents respectively in pivotal Potomac Primary on Tuesday.
This means they have seen the primary victories in Maryland, Virginia and Washington, DC.
Obama's victories were by large margins. He was gaining about three quarters of the vote in the nation's capital and nearly two-thirds in Virginia.
Celebrating eight straight victories over Hillary Clinton, the senator expressed confidence for the final victory.
"Today, the change we seek swept through Chesapeake and over the Potomac. This movement won't stop until there is change in Washington, DC and tonight we are on our way."
Meanwhile on the Republican side, John McCain beat his only challenger, former Arkansas governor Mike Huckabee in a tight race in Virginia and won the two other contests easily.
"Thank you, thank you voters of Maryland, Virginia and the District of Columbia for a clean sweep of the Potomac... of the Chesapeake primaries."
It takes 1,191 delegates to clinch the Republican nomination at the party's convention in St. Paul, Minnesota, and McCain appears to be on track to reach the target by late April.
