Presidential candidates have little reason to spend time and money in the Democratic strongholds of Maryland and D.C. But the campaigns are depending on supporters from those jurisdictions to march across the Potomac into Virginia, where there's a bitter fight for Electoral College votes.

"The campaign isn't taking anything for granted in Maryland, but given our proximity to Virginia, our job is to help win Virginia," said April Jordan, a volunteer for President Obama in Prince George's County. "Folks just want to be able to say they have a part in that."

Virginia slipped under the radar as a state up for grabs four years ago when President Obama claimed victory, but now both campaigns have large, energized organizations, and they're calling in reserves from neighboring states to help win the ground game.

Obama's campaign emailed Democrats in the District twice in two weeks to help knock on doors in Northern Virginia, and Marylanders frequently come down to pitch in and call Virginians from their local offices. Republican presidential challenger Mitt Romney has also relied on nearby supporters as part of a nationwide "adopt-a-state" strategy that encourages activists in solidly blue and red states to help out in battlegrounds.

Marylanders from Harford County also trek up to Pennsylvania to help sway that swing state as well.

"The Romney people like to have Maryland people come over whenever they can. They have half a dozen organized events bringing them over to Virginia and Pennsylvania," said Louis Pope, co-chairman of Romney's Maryland campaign. "We have a number of people, hundreds really, helping out."

But when state parties send troops across the border, it can roil local candidates who need support in their own races. And it often upsets majority Democrats and Republicans, who feel the presidential campaigns are writing them off.

"We're pretty focused on local races. But when we send out our list of events each week we say, 'Here's how you can go help the Virginia campaign,' " said Nick Jeffress, executive director of the D.C. GOP. "We're passively saying, 'If you want to do this we understand.' "

Virginia has also hosted Obama and Romney, their wives and their running mates dozens of times in recent months. Both candidates have largely spurned D.C. and Maryland. If Beltway residents want to catch the candidates in person, they'll have to come to Virginia.

"[Romney's] gotta spend time where he can impact the vote," said Gary Featheringham, a North Potomac, Md., resident who stopped by Romney's Fairfax City rally earlier this month. "It'd be a waste of time to be in Maryland."