UPDATE: Mitt Romney is the projected winner of both the Maryland and Washington, D.C., primaries. Romney received more than half of the vote in Maryland as of 8:15 p.m., according to Maryland's Board of Elections. As Rick Santorum, Romney's closest competition for the nomination, was not on the Washington, D.C., ballot, media outlets have already concluded that Romney has swept the race.

Romney was the clear Republican front-runner in Maryland and Washington, D.C., both of which, along with Wisconsin, on Tuesday held their Republican primaries, a collection of events expected to move Romney one step closer to the nomination.

While polling indicates Romney is favored to win in all three jurisdictions, he faces a tough race in Wisconsin, where recent polling indicates he only has a single-digit lead over fellow presidential contender Rick Santorum.

Although Santorum has avoided calling Wisconsin a must-win state to justify his continued existence in the GOP race -- unlike his home state of Pennsylvania, a win that he's acknowledged that he needs -- there will likely be a growing call for him to drop out of what has been characterized as a never-ending primary so Republicans can rally around Romney as he prepares to challenge President Barack Obama.

In Maryland and Washington, D.C. -- where Santorum does not even appear on the ballot -- Romney is already expected to emerge victorious. 

Maryland is an unlikely win for Romney in a general election against Obama, but the primary race places him closer to reaching the 1,144 delegates needed to give a candidate the nomination.  Registered Democrats outnumber Republicans by more than two to one, according to state election officials, and the state has not gone Republican for president since 1988. Still, in a nominating contest that has not produced a clear favorite among the American people, every delegate counts -- and Maryland has 37 of them.

Maryland's delegates are allocated through a combination of a winner-take-all system and a proportional distribution. Each congressional district has three delegates who must vote for whomever wins their district, while a remaining 13 delegates are awarded to the candidate who wins statewide.

Romney is overwhelming leading in Maryland, where Public Policy Polling reports 52 percent of likely Republican voters said they would cast their ballot for the presumed nominee, compared with 27 percent who supported Santorum, 10 percent for Newt Gingrich and 9 percent for Ron Paul. A poll conducted by Rassmussen reports last week found Romney was supported by 45 percent of Maryland's likely voters, compared to Santorum's 28 percent.

So far, Marylanders don't seem particularly excited to cast their ballots. According to local media reports, voter turnout - thus far - can barely be described as light, according to local media outlets, which report voter precincts have been largely empty during the day on Tuesday. Polls in the state close at 8 p.m.

Washington, D.C., is no battleground for the Republicans candidates -- as in Maryland, Romney is widely projected to pick up the district's 16 winner-take-all  delegates. There has been virtually no campaigning by the GOP hopefuls in the nation's capital, as their campaigns already know Republicans are unlikely to win the area in November. President Obama won 93 percent of the vote in 2008, according to CNN.

Romney's only formidable challenger, Santorum, did not file papers to run in the D.C. primary, another indication the small district will be yet another Romney victory.

As of now, the District of Columbia Board of Elections and Ethics reports voter turnout has been light on Tuesday morning and early afternoon.  Polls close at 8 p.m.

Where to Watch Maryland Primary Results Online:

The Washington Post is live blogging Tuesday's primary results as the day progresses here. In addition, national websites such as PolicyMic and The Huffington Post are live blogging the race until polls close on Tuesday night.

Local media outlets such as WBAL and the Baltimore Sun are also tracking Maryland's primary election results and voter turnout.

Presidential primary information can also be found on Maryland's State Board of Election's website.

Where to Watch Washington, D.C., Primary Results Online:

In addition to the Washington Post live blog, PolicyMic is also tracking the Washington, D.C. primary all day Tuesday.

Those interested in following the primary directly from the source can also follow the District of Columbia's Board of Elections and Ethics website, which will begin posting official results after 9 p.m.

Where to Follow on Twitter:

Search for the hashtags #Mdpolitics or #Mdprimary to foloow the conversation about Maryland's primary race. To follow the Washington, D.C. race, search the hastags #DCision2012,  #dcGOP and #dcprimary.