One of the richest villages in the United States, Northeast Harbor, faces a serious problem of decreasing year-round population and declining year-round business. How it handles this decline could offer lessons to other shrinking communities.

Northeast Harbor, a village in the town of Mount Desert, thrives in the summer with the influx of summer people, including several listed among the Forbes 400 richest Americans. But the year-round population, once about 900, has dropped to a current estimate of 350.

The Mount Desert Elementary School in Northeast Harbor has an enrollment of 167 — down from 222 in the year 2000. Mount Desert Regional High School now has only 17 students who live in Northeast Harbor out of its total 530, a big drop from the number 10 or 15 years ago, officials say.

Property values, rental prices and property taxes in Northeast Harbor have soared. Many residents have sold their homes to summer people and moved away, leaving the houses empty all winter. Fires in 2008 and 2009 destroyed four commercial buildings on Main Street, and only the Colonel’s Restaurant and Bakery has been rebuilt. The other three lots remain vacant.

The village no longer has a drug store, fish market or movie theater, as it did in days past. The co-owner of the Pine Tree Market on Maine Street, Aaron Gray, said he will try to stay open this winter. He and his wife, Erin, bought the business five years ago. He said business has been worse each year and now is “horrible.”

The village has several other anchor stores including the F.T. Brown Hardware Company, Sam Shaw’s jewelry shop, the Kimball Shop Boutique and the Holmes Store. Other village attractions are a new library, the well-managed harbor and marina with current plans for expansion and the active Neighborhood House.

Peter Godfrey, who helped found the Summer Residents Association nearly 40 years ago, said the village’s downtown “is dying unless something is done.” He urged prioritizing development such as construction of a first-class restaurant and a drug store and opening dialogue between summer people and year-rounders on how to achieve them.

Lanie Lincoln, until recently president of the Summer Residents Committee, is co-chairman of a Revitalization Committee created by the village selectmen. She expressed satisfaction with selectmen spending 45 minutes in early September discussing the matter and voting to spend $5,000 on the Urban Land Institute develop a plan.

Some wealthy summer people sound eager to help, and some winter residents say they should put their money where their mouth is. A plan agreed upon by summer and winter people could point the way.