The impending shutdowns — a trend that is expected to continue in the coming years — add to more than three dozen public schools that have closed or consolidated since the pandemic disrupted classroom learning. That list includes shuttered elementary schools in Cambridge, North Middlesex, and Wellesley, and approximately nine charter schools.

District leaders have pursued the closures and mergers to balance operating budgets amid declining enrollment and rising costs for special education, transportation, utilities, and other expenses, or to curb spending on replacing antiquated school buildings as construction costs have soared.

The efforts have sparked scores of protests from parents, educators, and other community members, who worry about losing close-knit communities and whether districts will be short on space if enrollment rebounds.

In Acton, Molly Sparrow will be constantly reminded of the Conant School’s closure long after the final bell rings in June. The school is across the street from her home, and her children, who attend the second and fourth grades there, will be reassigned to other schools under a plan to address declining enrollment.

“It was a very tough pill to swallow for me and my kids,” Sparrow said, but added that they have now “gone through the stages of grief” and are focused on building something positive for next year.

The consolidation and closures come as the state’s public school enrollment hit a 30-year low this year. The shrinking student population, which intensified during the pandemic and then again amid President Trump’s recent crackdown on immigration, has resulted in a growing number of empty classroom seats.

Just how much extra space is there? A recent report by the Massachusetts School Building Authority found half of the nearly 1,600 schools assessed last year operated at less than 80 percent capacity — more than twice the rate in 2010 — resulting in approximately 275,000 extra seats.

The MSBA anticipates more schools will close and merge in the coming years, noting it is working with a dozen districts, including Scituate, Westford, and Ipswich, on potential school construction proposals that could involve consolidating two or more schools. Some projects, such as one in Wilmington, have already received voter approval.

Many of those proposed mergers involve small elementary schools erected decades ago, which are often plagued with a variety of problems, such as outdated heating and electrical systems and undersized classrooms, or lack basic amenities like cafeterias or gymnasiums.

Swampscott, for instance, replaced three small elementary schools in 2024 with a new building that opened with more than 700 students.

But the promise of new buildings isn’t always enough to entice support for mergers, with voters rejecting such projects in West Bridgewater in February and Hamilton-Wenham in September.

Devotion to a cherished school can also motivate voters to approve hefty property tax hikes for operating budgets to avoid a closure, such as Belmont’s approval of an $8.4 million tax override in 2024 that saved one of its elementary schools.

So far, the more than three dozen schools that have closed or merged since the pandemic disrupted classroom learning have generated a small reduction in public schools statewide — about 2 percent, according to a Globe review of state data. Just over 1,800 schools are operating this year.

The downsizing is nevertheless amounting to the most active period since districts grappled with the financial fallout from the Great Recession about two decades ago, although at a somewhat smaller scale, the Globe review found.

The analysis relied on the overall number of public schools operating annually in Massachusetts over 20 years to track periods of contraction and expansion.

Compared with most other states, the current reductions in Massachusetts appear to be more robust. The nationwide closure rate hovers around 1 percent and has repeatedly fallen below that in recent years, according to a report last year by the Brookings Institution and IZA Institute of Labor Economics.

“Permanent school closures are a rare phenomenon‚” Sofoklis Goulas, the report’s author, said in an interview.

Given projections indicating public school enrollment will continue declining, Goulas said he anticipates more school closures in the future. A variety of factors, he said, are shrinking enrollment, including declining birth rates and an increase in parents choosing private schools, homeschooling, and other alternatives amid lingering concerns over pandemic learning loss.

“A recommendation would be to plan early because closures are a very painful thing for any community,” he said.

In Acton-Boxborough, Superintendent Peter Light said the district’s reorganization of its elementary schools, which calls for changing grade configurations and closing Conant, was an attempt to proactively address declining enrollment.

“Our buildings are not so substantially under capacity that this was a slam dunk,” he said. But he added, ”The resources flowing to the schools weren’t sufficient to keep doing what we need to do for kids.“

The district has cut dozens of positions in recent years, he noted, and finances will remain tight into the foreseeable future.

One of the most ambitious potential mergers is unfolding in Western Massachusetts. The Mohawk Trail and Hawlemont regional school districts are exploring a merger, which could result in closing all elementary schools and relocating students to Mohawk’s secondary school, which would be slightly renovated.

Martha Thurber, chair of the Mohawk Trail School Committee, said consolidating schools into a single campus is critical to ensuring the future viability of Mohawk Trail amid steep enrollment declines and escalating operating costs.

Many elementary school classrooms have only five or six students in them, she said, while merging could result in making unique programs at various elementary schools available to all students, such as an agricultural program at Hawlemont Regional School, which includes a barn with animals.

But convincing voters to support the proposal will be “a hard slog,” with many questions raised about long bus rides and what to do with the empty buildings.

“There are a lot of folks who don’t want to lose their elementary school,” she said. “Our real challenge is to make them see they are not losing an elementary school, they are gaining something much better.”

Across Massachusetts, scores of shuttered schools have been converted into housing or spaces for administrative offices, community organizations, or preschool programs.

In Newton, debate over merging the approximately 100-year-old Underwood and Ward elementary schools into a proposed new building has dragged on for seven years.

Parents are worried that consolidating would obliterate the small neighborhood feel of their schools, which each have fewer than 300 students and are about a mile apart.

“It really is the heart of the community,” said Maggie Elitt, of the Underwood, where her daughters attend the second and fifth grades.

Amy Davis, who has a fourth-grade daughter at Underwood, said she is worried Newton hasn’t thought through the merger, noting Underwood’s enrollment is rebounding amid a districtwide decline in students.

“The general consensus of Underwood is just leave us alone, we are good, our school is 100 years old, and the gym ceiling leaks a little bit, but we are happy for the most part,“ Davis said. ”It would be cool to have a new school, but it’s OK if we don’t.”

Josh Morse, chief operating officer for the City of Newton, said the city is carefully evaluating enrollment trends.

“The question is, when we build a new school, are we going to see an increase in the number of students who come back into the public school system?” he said, noting several parents have opted for private schools because of building conditions. “That variability makes the decision about consolidation even more challenging because we want to make sure that we don’t make a mistake.”

Christopher Huffaker of the Globe staff contributed to this report.

James Vaznis can be reached at james.vaznis@globe.com. Follow him @globevaznis.