JUSTIN COOK The Roanoke Times

Virginia Tech sophomore Alyse Cruickshank registers a voter in Blacksburg. Many of the state's new voters are younger than 25.

JUSTIN COOK The Roanoke Times

Alyse Cruickshank (center) registers Josh Minnit (left) and Christian Roa to vote at Virginia Tech in Blacksburg.

If you're planning to vote in this year's presidential election, you may have a longer wait at polling places in the Roanoke and New River valleys.

Mirroring a statewide trend, voter registrations are up by more than 30,000 across the region, most dramatically in Montgomery County, which has more than 10,000 new voters compared with the election of 2004.

Political observers say the dramatic increases seem to point to the Barack Obama campaign's aggressive ground game. From the beginning of the year, there has been a powerful push to register as many voters as possible especially in areas where the majority would likely vote for the Democrat.

But it's hard to predict precisely in which candidates' favor those votes will fall, because in Virginia voters do not register by political party.

Larry Sabato, director of the University of Virginia Center for Politics, said, "It's possible that Republicans in disproportionate numbers have registered this year because they're worried about Obama. I would bet they are largely Democrats, but I don't know that."

Trixie Averill, a Republican who was a delegate to her party's convention in August, noted that nearly 2,000 new voters have signed up in typically Republican Roanoke County, where she lives, since July. That's when the campaigns for both Barack Obama and John McCain were picking up steam.

Is the increase a sign of support for the Democrats, as is widely supposed partly because their Virginia primary turnout hugely exceeded the Republicans' total? Not necessarily, Averill said.

"I've been doing my own private polling at the grocery store, the gas station, and wherever I go I wear my McCain-Palin button. I can't tell you how many people have been stopping me to ask where they can get a [McCain] button or a yard sign."

Since the last presidential election, the number of registered voters in the state has ballooned by 504,000, according to data from the Virginia State Board of Elections. More than 5 million Virginians are registered to vote now.

To put that number in perspective, George W. Bush beat John Kerry in Virginia in 2004 by 262,000 votes. That's just more than half of the total number of new voters to register since then.

Notably, 96 percent of the increase has come just this year, and more than half of it since July, shortly after McCain and Obama each secured his respective party's nomination.

Of the 25 localities with the greatest gains in voter registration this year, Gov. Tim Kaine, a Democrat, won in all but four in 2005. Of those same 25, Jim Webb won all but eight in his successful 2006 Senate bid against incumbent George Allen.

Those include Roanoke and Montgomery County, both of which went for Kaine and Webb.

Those are increases that would seem to favor Obama.

But some would seem to favor McCain, in places such as Chesterfield, Hanover, Spotsylvania and Stafford counties, all of them Republican strongholds.

Some are also in Tidewater communities such as Virginia Beach, Newport News and Hampton. While those areas have leaned Democratic recently, they also have large military populations likely to favor a Navy veteran and former prisoner of war like McCain.

In Montgomery County, home to the state's biggest university, Virginia Tech, registrations jumped by about 10,500, or 23 percent, compared with 2004. That would seem to reflect statewide numbers in which 40 percent of newly registered voters are under 25 years old.

"From a partisan perspective, I think it bodes well for Barack Obama and the Democratic Party," said Steven Cochran, Montgomery County Democratic chairman for 11 years. "I know these volunteers have been doing a lot here canvassing for new supporters."

Roanoke, a rare Western Virginia locality that last voted for a Republican in a presidential election in 1984, now has 5,250 more voters than it did four years ago.

Democratic organizers such as Joseph Hancock have been busily canvassing Roanoke neighborhoods; he said they've signed up about 3,000 new voters since February.

"We initiated a membership drive in every area of the city of Roanoke that you can think of," Hancock said.

Roanoke County gained 4,629 voters over the past four years.

"I think Roanoke County is going to go Republican," said Averill, "and I'd like to think that as Roanoke County goes, so will the commonwealth."

But until Nov. 4, it's still all guessing and hoping.

Even if all these new voters are "predominantly Democrat, there are going to be 35 [percent] to 40 percent Republicans," said Sabato. "But anybody who says that all of this is Democratic is dreaming."

matt.chittum@roanoke.com 981-3331

rob.johnson@ronaoke.com 981-3234