Mitt Romney has swept the Republican primaries in D.C., Maryland and Wisconsin, as projected by NBC News.
NBC called the D.C. and Maryland primaries as soon as polls closed at 8 p.m., but it was closer in Wisconsin, where polls closed at 9 p.m.
In Maryland, the front-runner Romney has a significant lead over former Sen. Rick Santorum in Maryland, with former House Speaker Newt Gingrich and Rep. Ron Paul trailing far behind. Romney should take the bulk of Maryland's 37 delegates -- 24 are awarded based on results in the eight congressional districts, 10 go to the candidate with the most votes statewide and three are superdelegates not bound by the vote (two superdelegates have endorsed Romney). Romney has 28 of the delegates with nine remaining to be allocated, the Associated Press reported.
Santorum was not on the D.C. primary ballot. Romney will win D.C.'s 19 delegates in that winner-take-all primary. A Republican candidate has never carried the District in a presidential general election.
With former Gov. Robert Ehrlich heading Romney's Maryland campaign, the former Massachusetts governor had the greatest organized presence in the state, the Associated Press reported. Restore Our Future, a super PAC that backs Romney, spent more than $450,000 on a television ad campaign in Maryland.
Santorum didn't campaign in Maryland, opting to focus on Wisconsin. Gingrich campaigned Monday in western Maryland and visited Annapolis and the Eastern Shore last week. Paul spoke last week at the University of Maryland in College Park.
Maryland appeared to be headed toward a low turnout, even for a primary. In 2004, voter turnout was about 27 percent, and in 1996, the turnout was 25 percent, according to Linda Lamone, the state elections administrator, who noted that both of those primaries also featured an incumbent president running for re-election.
Romney's campaign sent a few staffers to the District to help with get-out-the-vote efforts. The only candidate to make a campaign appearance in the District was Gingrich, who delivered a speech to Georgetown University students that made no mention of the primary.
D.C.'s Republican leadership united behind Romney, and the former Massachusetts governor won a straw poll at a GOP fundraising dinner last week with 72 percent of the vote. No other candidate received more than 9 percent, the AP reported.
Jon Huntsman, who has suspended his campaign, also was on the District ballot.
Many D.C. Republicans are outspoken in favor of giving the city a voting representative in Congress, which puts them at odds with many in their party. None of the active GOP presidential candidates has taken a position on voting rights, the AP reported.