Knock-knock. Is anyone home at Donald Trump’s N.H. campaign?

Donald Trump arrived for a campaign event at the Atkinson Country Club in Atkinson, N.H. in October 2015. Dina Rudick/Globe Staff

MANCHESTER, N.H. — Ahead of Donald Trump’s planned visit to the state on Monday, many New Hampshire Republicans are increasingly concerned about his nearly nonexistent campaign here.

And here’s one reason why: In the middle of a workday this week, Trump’s state headquarters was locked, windows covered in paper, and displayed a note for visitors to call a phone number for access. By the door, there were about a half-dozen large blank posters, with this message clothes-pinned to the boards: “For the Donald Trump campaign. He’s embarrassing, but he’s ours.”

Meanwhile, just a few miles away, Hillary Clinton’s New Hampshire office has five full-time staffers, including a state director, a deputy state director, a communications director, a digital director, and a political director. And they’ve all worked in New Hampshire politics for years.

“The concerning thing is that there appears to be no sense of urgency from the Trump campaign for the battle ahead,” said former New Hampshire Republican Party chairman Wayne McDonald. “The Clinton campaign is up and running, and while I believe that Democrats are more divided than we are at the moment, our side is unnecessarily playing catch up, and I am not sure when it will get better.”

Asked about the state of Trump’s campaign in New Hampshire, Steve Stepanek, Trump’s state cochairman, pointed out that about 10 percent of the entire Trump national staff has New Hampshire roots, including the campaign manager, Corey Lewandowski, and the newly installed national political director, Jim Murphy.

“There is a deep belief within the Trump campaign that the grass-roots matters, and we already have a great grass-roots team here that no one gives us credit for,” said Stepanek, referring to the campaign’s volunteers during the primary.

Overall, Trump has a much leaner staff than Clinton. A recent Globe analysis showed Trump’s campaign was just 17 percent of the size of Clinton’s operation. Trump came under fire last year as well for having a much smaller staff compared to his GOP rivals — all 16 of whom he defeated to win the nomination.

In the middle of a workday this week, Trump’s state headquarters was locked. James Pindell/globe staff

Trump has defended the relatively small size of his campaign staff, tweeting this week that “small is good, flexible, save money and number one!”

Trump’s national spokesperson did not return a request for comment on the size of his New Hampshire staff or office hours. New Hampshire has four votes in the Electoral College, but it is nonetheless a heavily contested state in presidential races.

Trump is scheduled to return to New Hampshire on Monday to attend a high-dollar fund-raiser and deliver a speech at Saint Anselm College. It’s his first trip to New Hampshire since he won the first-in-the-nation primary by 20 points in early February.

After the primary, nearly all of Trump’s Granite State staff moved on to work on later nominating contests. In the months since the New Hampshire primary, the Trump campaign locally has been largely run by an office manager who opens the headquarters but without regular hours.

There are more disparities between the two campaigns. The Clinton campaign has held local press events hitting Trump that go unanswered because no one from Trump’s campaign is there to rebut the charges. In addition, a super PAC supporting Clinton is running millions of dollars worth of television ads with an anti-Trump message. At the same time, donors are unsure to which of the rival Trump super PACS they are supposed to give — suggesting those pro-Clinton paid ads could go unanswered for weeks.

James Pindell/globe staff

Clinton’s top state staff has had ongoing outreach to supporters of US Senator Bernie Sanders, in an effort to unite the party, according to campaign sources. Meanwhile, Trump’s campaign supporters ousted the state party chairwoman, Jennifer Horn, as leader of their delegation to the national convention in Cleveland.

“The Trump campaign has been able to get a lot of voter enthusiasm among Republicans, but they aren’t capturing any of this energy and channeling it into ways that can help the campaign like getting volunteers to get people registered to vote or making phone calls,” said Ryan Williams, a former Mitt Romney staffer and Republican consultant who has worked in New Hampshire politics for nearly a decade.

At the moment, the Trump campaign has relied on the Republican National Committee — which has had paid staff in New Hampshire since last year — for its ground support. In late May, the RNC circulated a memo saying it will have 29 staffers doing political field work in New Hampshire.

So far, polls have shown the disparity in ground game has not had a major impact on the race. Two recent surveys, from Franklin Pierce University and WBUR/MassINC, show Trump and Clinton in a statistical tie. Both campaigns held events for supporters in the state on Tuesday night, marking the unofficial kick-off of the general election.

New Hampshire state Representative Fred Doucette, a New Hampshire leader for Trump, pointed out that nearly 200 volunteers march for Trump in a local Memorial Day parade.

And as Southern New Hampshire University political scientist Dean Spiliotes points out, Trump has defied so many normal political rules this year it is possible that he could get by without the traditional local campaigning — or the accompanying staff.

“He has an ability to get his message out so many ways and does it so well it is unclear that he will need a traditional campaign anyway,” Spiliotes said.