When 18-year-old Sue Collins of Caribou boarded a plane one winter day in 1971, she couldn’t have imagined where it would take her.

“I had never met a senator,” she recalled recently. “I had never been to Washington. I had never even flown on an airplane.”

Chosen as one of two students from Maine to get an up-close view of the U.S. Senate, Collins wound up in the private office of Sen. Margaret Chase Smith, her state’s legendary senior senator — the only woman serving with 99 men.

For two hours, Smith talked with her about everything from the armed forces to the definition of full employment. One of Smith’s messages that came through loud and clear was the importance of “standing tall for what you believe in,” Collins said.

Amazed at the opportunity given her as a high school senior, Collins remembered thinking afterward “that women can do anything.”

“That pivotal meeting,” Collins said, “was the beginning of my journey to the Senate.”

Now finishing her second decade in office, Collins has the distinction of hailing from a state with the best record in the country for electing women to the Senate.

A century after Montana’s Jeannette Rankin won a House election — the first woman to serve in Congress — women remain a distinct minority on Capitol Hill, holding only one in five seats.

Maine voters, though, have proved kinder to female Senate candidates than any other state and have one of the best records of electing women to Congress generally.

Half a century ago, Rankin saw too few women following in her footsteps.

“We’re half the people,” an 86-year-old Rankin told Newsweek then. “We should be half the Congress.”

But led by a trio of long-serving Republicans, Maine has had at least one woman representing the state on Capitol Hill since 1940, with the exception of a one-term, six-year break in the 1970s.

Its three female senators — Republicans Smith, Olympia Snowe and Collins — collectively represent 62 years of Senate service, easily the best record of any state. Twenty-one states have yet to elect a female senator.

Smith, Snowe and Democratic Rep. Chellie Pingree have held House seats as well, landing Maine among the handful of states with the best record of electing women to the House, too, despite the small size of its delegation.

Smith provided “the galvanizing moment” for Maine’s unusually receptive response to women candidates, said Emily Cain, executive director of the Washington-based Emily’s List that has been pushing for decades to increase the number of women in Congress.

Cain, who lost two Maine congressional bids, said Chase’s success offered “a stellar example of leadership for all people in Maine” for decades, and it showed women in particular that they could succeed in politics.

Collins, who uses the same desk on the Senate floor where Smith once sat, said that back in 1971, it wasn’t so obvious to young women that all paths were open to them.

It made such a difference, she said, to see Smith holding office, a strong woman who had earned the nation’s respect. Collins said her example opened the door for other women to serve in public office in Maine.

Snowe once called Smith “a role model for countless more women across America who never before thought they could aspire to any kind of public office. Certainly she paved the way for me.”

“You can’t be what you can’t see,” Cain said. When young women saw Smith, they realized that holding elected office was “now on my list of things I can be when I grow up,” she said.

“Indeed, it was somewhat ironic that, even as Smith never liked to overemphasize the role of women in politics, she made an enduring difference for women,” Snowe wrote in a tribute to her predecessor.

At least half of Maine’s four-person congressional delegation has been female for the past two decades. For one four-year stint, three were women.

Sen. Angus King, a Maine independent, said part of the reason Maine’s voters may have proved more receptive to female candidates is “the intimate nature of Maine’s politics.”

“People know each other,” he said, so they can make judgments at the polls based on who the contenders really are, rather than their age, gender or other artificial distinctions.

Collins speculated that northern New England’s long-standing tradition of equality of participation between men and women in town meetings and elections may also play a role in Maine’s openness to representation by women.

With women making up only about a fifth of Congress — much lower than their percentage in the legislatures of most Western countries — there’s still plenty of room for growth in their numbers.

Two states, Mississippi and Vermont, have yet to elect a woman to Congress. Delaware’s first took office only this year.

And Montana, which elected the first woman to Congress in 1917, has never had another.

After Rankin, only a smattering of women from anywhere managed to serve until the Great Depression. Most of them were appointed to fill short vacancies.

In Smith, Maine elected the first woman to log a lengthy stint in the Senate without inheriting the seat from her husband. Smith served in the House for eight years before winning a Senate seat she held for a quarter-century.

After Smith’s Watergate-era departure, Maine lacked a female standard-bearer in Washington until Snowe won a House seat in 1978, at a time when the number of women had begun to grow.

Snowe moved up to the Senate in 1995, where Collins joined her two years later. They served together until 2013, when Snowe opted to retire.

In part because of pioneering female candidates, the future looks brighter for their numbers in Congress.

Cain said young women are flocking to candidate training sessions in record numbers.

Women, she said, are seeing what’s going on and telling themselves, “Enough is enough.”

Historically, Cain said, Emily’s List had to search out women to run and beg them to do it.

“Now they’re banging down the door,” Cain said, so more change “is going to happen a lot sooner” as a consequence.

Perhaps one of them will follow Collins’ lead.

Collins said she knows the importance of role models and feels “a special obligation to help lift the aspirations of the girls that I talk to.”

She said that’s one reason she has visited more than 200 schools across Maine.

“I want those little girls to see they can grow up to be a senator,” Collins said.