Maryland voters headed to the polls Tuesday to decide a mixed bag of primaries, with a handful of competitive races scattered among several more where incumbents are expected to hold their seats with ease.

With polls open statewide until 8 p.m., the marquee matchups are unfolding in Rep. Roscoe Bartlett’s (R) 6th District, which was redrawn by Annapolis Democrats to include the western portion of Montgomery County and is now considered a tossup in November.

Bartlett is looking to fend off seven Republican foes, including state Sen. David Brinkley (Frederick) and Del. Kathy Afzali (Frederick), in his quest for an 11th term. On the Democratic side, state Senate Majority Leader Robert J. Garagiola (Montgomery) and financier John K. Delaney have engaged in the state’s most heated and expensive primary matchup.

Garagiola is the favored pick of much of the state Democratic Party establishment, including Gov. Martin O’Malley (D), and the 6th District’s lines were drawn to be favorable to him. But Delaney, a first-time candidate, has balanced the scales by heavily outspending Garagiola and by winning the endorsement of President Clinton.

In the Republican presidential contest, former Massachusetts governor Mitt Romney is considered the favorite. Sen. Benjamin Cardin (D) is expected to hold off a Democratic primary challenge from state Sen. C. Anthony Muse (Prince George’s), while former Secret Service agent Daniel Bongino and former Defense Department official Richard Douglas are the leading candidates in the Republican race to face Cardin.

With no presidential primary on the Democratic side and relatively few tight contests, turnout was expected to be low across the state. Margie Roher, spokesperson for the Montgomery County Board of Elections, said that although official tallies are not reported to the board until late in the day, the number of voters who cast ballots in Tuesday’s primary election appeared to be “extremely low” across the county.

Garagiola said Tuesday morning he hadn’t seen many voters so far.

“Turnout looks low, which is what we expected with spring break, and also because of redistricting, people aren’t sure what district they’re in,” Garagiola said in an interview after visiting Lake Seneca Elementary School in Germantown.

Delaney said turnout was difficult to gauge, but he was encouraged by the response he’d seen at the polls Tuesday and in recent campaigning.

“I’ve noticed at the Metro stations . . . when I first went out there five or six weeks ago no one knew who I was, and now everyone recognizes me,” Delaney said.

At the Potomac Community Center, only 46 of the 1,757 voters registered had cast their ballots by 9:15 Tuesday morning. Outside, near the entryway decorated with red, white and blue flags, campaign volunteers and precinct officials expressed disappointment about the low turnout as they scanned the parking lot for newly arriving voters. The community center is generally one of Potomac’s most active — and largely Democratic — precincts, officials said.

Terry Ao, a Potomac resident since 1999, said she supported Garagiola in the 6th District Democratic primary because she felt he echoed her social values.

“I am a civil rights attorney working for a nonprofit in D.C., and I felt that he spoke the most to my issues and concerns,” she said.

Ao said she is particularly focused on the needs of the region’s “vulnerable communities,” and felt that Garagiola “would be a champion for them.”

George Guess, 67, chose Delaney. Guess said he was impressed by the fact that Delaney’s campaign had a strong grass-roots presence, with volunteers who had come through neighborhoods to knock on doors.

“He struck me as close on the issues to Garagiola, but Delaney was endorsed by Clinton, and he had all those guys on the ground rather than just calling,” Guess said. “I thought that was more sensitive to the people, less canned.”

Seth Ross, 17, a lifelong Potomac resident, also voted for Delaney and was similarly impressed by Clinton’s endorsement.

That was what really swayed him, said Ross, who will turn 18 in August and will vote for the first time in a general election this fall.

“I was really for Hillary, so the endorsement of the Clintons definitely mattered,” he said.

John Delaney’s wife, April Delaney, made a brief appearance at the Potomac Community Center on Tuesday morning on her way to Gaithersburg High School.

Wearing her husband’s campaign sticker on her jacket, April Delaney said she was pleased by the number of voters she’d met Tuesday who said they supported John Delaney.

“We’re very excited, there’s a lot of momentum,” she said, adding that the couple had dozens of friends volunteering at polling sites across the district.

Though the support of voters was encouraging, April Delaney said she had hoped to see more people at the polls.

“I wish more people would be involved and turn out for primaries,” she said. “You can’t complain about your government if you don’t vote.”

Daphne Bloomberg, who has been a precinct official for the Democratic Party at Potomac Community Center since 1990, said she was decidedly unimpressed by John Delaney’s campaign.

“I have never met Mr. Delaney, ever,” said Bloomberg, who is also the chair of the District 15 Democratic caucus.

“I’ve seen him speak, but he doesn’t shake hands,” Bloomberg said, adding that while Delaney has many “minions” going door-to-door in local neighborhoods, he “doesn’t do his own grass-roots work.”

“This is a bought election,” she said of the financier, who has poured more than $1.7 million of his own money into his primary bid.

“I know Ben Cardin, I know everybody on the campaign list,” Bloomberg said, shaking her head. “But I don’t know John Delaney.”

Karen Atchinson, a Potomac resident who voted at Potomac Community Center on Tuesday morning, had her own theory about why few voters seemed to be casting ballots. For the majority of the 40 years that Atchinson has lived in Potomac, she has been a voter in the 8th district, not the 6th, she said.

“I’m frustrated, and I think there is a lot of frustration,” she said. “I think that’s part of why the turnout is low here.”

At Potomac United Methodist Church, the handful of polling booths sat mostly empty Tuesday morning, with a slow but steady trickle of voters coming through to cast their ballots.

“I’m optimistic, though,” election official Janet Millenson said. “We have several competitive races going on. It’s been fewer voters than we would like to see, but it’s still early.”

Michael Flynn, 64, a bank official who has lived in Potomac for 24 years, said he supported businessman Brandon Rippeon in the Republican primary against Bartlett.

“I’ve read some of [Rippeon’s] literature, and I feel he is the right man for the job. I think he’s a stronger candidate than Roscoe Bartlett,” Flynn said. “I think Bartlett is too conservative, and his approach is often shoot from the hip, rather than thoughtful.”

Flynn added: “The way the Democrats gerrymandered this district to try to take control is shameful.”

Roger Thies, another Republican voter at the precinct who has lived in Potomac for 24 years, echoed Flynn’s frustration about the new 6th district lines. But Thies supported Bartlett, he said, because he felt he was the GOP’s best bet at retaining control of the competitive seat.

“Clearly the Democrats have tried to gerrymander [the district], and I think Bartlett has the best chance to hold it, on name recognition alone,” Thies said. He said it was the “sole reason” he cast his ballot for Bartlett.

The Republican incumbent also had some support at Hillcrest Elementary School in Frederick.

“He’s been good to the farmers in Frederick County,” retiree Millie Cody, 64, said of Bartlett. “And he’s always standing up for our family values.”

Henry Brown, 71, a Democrat who felt “outnumbered” by Republicans at the polling place, said he voted for Delaney because, “If it’s good for Bill Clinton, it’s good for me.”

Turnout also appeared light in Rep. Chris Van Hollen’s (D) neighboring 8th District.

“To call it a steady trickle would be overstating it,” said Heather Dlhopolsky, a volunteer for the Democratic Party shivering at a table outside Walter Johnson High School in north Bethesda.

At Richard Montgomery High school in Rockville, Bill Dillinger, 73, a retired federal employee, waited outside the polls with his dog while his wife cast her ballot. When it was his turn, he said he voted for Van Hollen and Cardin, but reluctantly.

“I think we ought to throw them all out, or 75 percent of them out,” he said, because of the persisting economic problems and political gridlock.

Walking out of the polling site at Bethesda-Chevy Chase High School, Don Allen said he voted for Cardin. Though he said he thinks there should be more African-Americans in Congress, he thought Muse — who opposes same-sex marriage — “was too far to the right on social issues.”

Allen added that he voted for Van Hollen because he’s been effective in Congress. Several other Democrats said the same thing; one didn’t even know there was another candidate.

Among the poll workers at Charles Carroll Middle School in New Carrollton, there was plenty of time to tell stories of how the same location had been packed during the presidential primary four years ago, because inside there were no voters and outside no poll workers.

A total of 87 voters had cast ballots by 1 p.m., according to the precinct captain. “It is a sad commentary that so few people failed to exercise their right to vote when so many others sacrificed for this day,” said Richard Knight, 59, one of the few who came to cast a ballot.

Cynthia Holley, 67, said many probably skipped voting because they are focused on the general election.

Holley, who is African American, she said she voted to reelect Cardin over Muse because “President Obama endorsed him.”

Some Democrats took issue with Muse’s record on abortion rights. He has opposed abortion, and he says the public should be better advocates for abstinence. “

I didn’t even know Democrats could be anti-choice,” said Katharine Rogers, 79, a retired English professor, after she left the voting booth in North Bethesda Middle School. She voted Cardin.

Howard Miller, a retired school administrator in Prince George’s County, was undecided about the Senate Democratic primary as he walked up to his polling place at Evangel Cathedral, a mega church and one of the largest precincts in the state.

“Muse or Cardin? Muse or Cardin?” he said to himself as he stepped one foot in front of the other.

He stopped to chat with Cardin, who rattled off his record of helping the county - money for the Metro system, money for pediatric dental clinics, bringing federal funds to the county. But Miller was still uncertain.

Miller also likes Muse, who, like Miller, “is a Christian.” And while Miller himself does not support gay marriage, he said he worried that Muse’s positions against abortion and opposing gay marriage could serve to isolate Muse if he made it to the Senate.

“I am worried that I would be electing an island,” said Miller, who lives nearby the church in the Cameron Grove retirement community.

While Cardin appeared at the church without any local elected officials with him, several including County Executive Rushern Baker III(D) and State Sen. Joanne Benson (D-Prince George’s) have campaigned with him during recent weeks.

“I am proud of what I have done for Prince George’s and for all of Maryland,” Cardin said.

As for Miller, his vote will remain a secret, he said.

Staff writers Jeremy Borden, Michael Chandler, Caitlin Gibson, Hamil Harris, Miranda S. Spivack, Ovetta Wiggins and Victor Zapana contributed to this report.