Green Mountain College announced Wednesday that it will close at the end of the spring semester.

The college, a small private institution in Vermont, has a 185-year history and is known for its environmental programs. But the college's announcement said it couldn't attract enough students or a partner to maintain operations in a way that served students. Closure is expected after the end of this semester.

The news is likely to add to concerns about the health of small private colleges that don't have substantial endowments or large student bodies. New England institutions appear particularly vulnerable. Just last week, Hampshire College in Massachusetts announced that it was exploring partnerships and wasn't sure it would admit freshmen for the fall. Another Massachusetts institution, Newbury College, announced in December that it would close at the end of this academic year. And Mount Ida College, located outside Boston, announced in April that it would close. Also last year, Atlantic Union College, also outside Boston, announced that it would close.

The College of St. Joseph, in Vermont, nearly closed last year but said it would try to keep operating. Its goal has been to hit an enrollment of 235.

Colleges in New England are not the only ones facing tough times. Bennett College, a historically black women's college in North Carolina, is at risk of losing its accreditation, which would likely lead to the college's closure.

Barbara Brittingham, president of the New England Commission of Higher Education, accreditor to all of these institutions, said via email Wednesday evening that the association has been in regular touch with Green Mountain.

"The leadership at Green Mountain College has worked very hard to find options for their students in these difficult circumstances," she said.

Asked if she expected more closures, she said, "Likely so, though I wouldn't put a number on it. The demographics in New England are very challenging, and the farther north you go, in general, the more challenging it gets."

Robert W. Allen, Green Mountain's president, announced the news in a letter on the college's website.

"The decision to close Green Mountain College comes only after a tireless pursuit of multiple options to remain open, including the rigorous search for new partnerships and reorganization of our finances," said the letter. "Despite our noteworthy accomplishments related to social and environmental sustainability, we have not been able to assure the economic sustainability of the college. Financial challenges are impacting liberal arts colleges throughout the country and Green Mountain College is no exception. These financial challenges, the product of major changes in demographics and costs, are the driving factors behind our decision to close at the end of this academic year."

Green Mountain is working with Prescott College, in Arizona, to enroll its students who won't finish degrees this year. Prescott and Green Mountain are members of the EcoLeague, a group of six liberal arts colleges with an environmental focus. Sterling College, which like Green Mountain is in Vermont and focuses on the environment, also announced that it would work to welcome students from Green Mountain.

According to the latest Education Department data, Green Mountain enrolls 492 students, all undergraduates. Another department database indicates that Green Mountain has been admitting more than three-quarters of applicants but enrolling only about 20 percent of those admitted.

On social media, Green Mountain alumni mourned the college, noting qualities about it they loved, generally the environmental focus and a personalized education in an intimate environment. Many comments were like this one from an alumna: "So much a part of my development of the person I am today …"

Wrote another alumna, "I don’t know how many times I’ve said it or who first told me. Every high school has that kid who is a needle in the haystack. The weird kid that didn’t quite fit in. All of those needles found their home at Green Mountain College. Heart broken. GMC built a huge piece of who I am. I walked in as an insecure freshman who just wanted to play outside and walked across the stage having seen the world, mountaineered & sea kayaked in Patagonia, lived and worked with women in Mexico and had dreams, aspirations and career goals. Thanks for helping me embrace my weird GMC. I’m sad for the current students, and all the needles in high schools who will not have a home to find."

Of course those are not qualities that necessarily pay a college's bills. Bryan Alexander, a consultant and writer about higher education, said via email, "Demographics drives this, especially in aging and no-growth regions like Vermont."