U.S. Rep. Chellie Pingree has a commanding lead over Republican challenger Mark Holbrook headed into the November election, according to the latest polling for Maine’s 1st District.

Pingree, a Democrat seeking a fifth term in Congress, had the support of 64 percent of likely voters versus 22 percent favoring Holbrook in a Portland Press Herald poll conducted by the University of New Hampshire Survey Center. Twelve percent of respondents remained undecided in the race, while 2 percent said they were supporting another candidate. The poll of 266 likely voters was conducted between Sept. 15 and 20, with a margin of error of 6 percent.

A self-described progressive, Pingree was the pick for nearly all of the Democrats surveyed and roughly one-half of the independents. Just 19 percent of Republicans said they would vote for the North Haven Democrat, compared to 59 percent who said they planned to support Holbrook.

But poll questions about whether respondents viewed the candidates in a positive light suggested that Holbrook – a clinical psychologist residing in Brunswick – is still relatively unknown in Maine’s southern congressional district.

When asked whether they had a favorable or unfavorable opinion of Holbrook, 74 percent of poll participants said they didn’t know enough about the Republican to say either way. Among those with an opinion, 10 percent regarded Holbrook favorably, 7 percent had an unfavorable view and 9 percent said they were neutral on the candidate.

Pingree was viewed favorably by 50 percent of respondents and unfavorably by 22 percent, while 9 percent had neutral views of the congresswoman. Nineteen percent of respondents said they did not know enough about Pingree to have an opinion.

Holbrook defeated opponent Ande Smith by just 57 votes during the Republican primary in June. The race was so close that Smith requested a recount from the Maine Secretary of State’s office; however, the outcome did not change.

The 1st District race has, to date, been overshadowed by the more competitive race just to the north between Rep. Bruce Poliquin, R-District 2, and Democratic challenger Emily Cain. While the national parties and political organizations are dumping hundreds of thousands of dollars into the 2nd District race, the contest between Pingree and Holbrook has been low-key to date because of Pingree’s perceived advantage in the district and her enormous fundraising advantage.

A former police officer who has also worked as an instructor and a lobsterman, Holbrook currently works with law enforcement officers, veterans and other clients at his psychology practice. He has accused Pingree of failing to represent the interests of Maine’s 1st District and pledged to bring a more conservative approach to Washington.

In an interview, Holbrook said he is attending meet-and-greet events and political forums as well as meeting with groups as he tries to build his support and name recognition. The candidates have also agreed to two televised debates so far.

“We can’t outspend Chellie Pingree but we can outwork her,” Holbrook said. “I’ve been working on this for 20 months. It’s been a long job interview … and we’re working hard meeting people.”

Pingree was first elected to Congress in 2008 and has been handily re-elected since. In 2014, Pingree won 60 percent of the vote in a three-way race. She did not face a Democratic challenger in this year’s primary.

According to the most recent campaign finance documents, Pingree completed the fiscal quarter that ended June 30 with more than $485,000 in her campaign account. Holbrook ended the same period with just over $1,400 following his primary competition with Smith. Holbrook had raised nearly $40,000 through June 30.