The congregation of Old Ship Church in Hingham — where services have been held in the historic wooden meetinghouse since 1681 — has decided to downsize, sort of, and sell its relatively younger, 150-year-old parish house.

The Unitarian group plans to use the proceeds — the asking price for the house and the prime land it sits on is just under $4.8 million — to build a smaller, energy-efficient, handicapped-accessible parish house on vacant land next to the meetinghouse.

“We’re a healthy, thriving congregation, and we want to stay that way,’’ said the Rev. Ken Read-Brown. “This would be a way to focus more on our programs — and not have to sustain two historic buildings.’’

Old Ship’s 250-member congregation voted overwhelmingly on May 1 to sell the parish house, which sits on nearly 3 acres across the street from the meetinghouse on Main Street in Hingham Square.

Built in 1867 as a single-family home by the Whiton family, who owned Hingham’s premier rope-making business, the imposing property was acquired by Old Ship in 1956, added onto in the 1960s, and is used for church classes, meetings, and functions.

In the past, a nursery school used space in the building, and both the New England Conservatory and South Shore Conservatory held classes there

Nina Wellford Price, president of Old Ship’s board of trustees, said maintaining the old house is expensive. Just repairing the circular driveway in front was estimated at $50,000, and a financial analysis found that about $700,000 in work on the building would be needed in the near future, she said.

But more importantly, she said, the top floors of the three-story building are not handicapped-accessible.

“We want to be accessible to everyone,’’ she said. “We need to make the buildings fit our needs, rather than vice versa.

“We had an ‘aha’ moment when we realized we could sell this beautiful property — have somebody do with it what it deserves — and at the same time meet our needs better by building something new, and green, and accessible and next to our meetinghouse,’’ she added.

The listing with Home Center Sotheby’s International Realty says the house is a “magnificent and significant historic landmark on Bachelor’s Row/Lower Main Street’’ and has 10,824 square feet, with six bedrooms, six baths, six fireplaces, and 11-feet-tall ceilings.

“There are possibilities for expansion or a 1-2 lot subdivision, but purchased as a single family home in this PRIME location, it could become THE HOME in Hingham,’’ the listing reads.

The property, which went on the market on May 5, is the priciest in Hingham currently, according to listing realtor Gail Bell, but not the most expensive ever. That distinction goes to a 9,900-square-foot home on 2.3 acres in World’s End, which sold a couple of years ago for $7.15 million, she said.

Bell said that several developers and individuals are interested in the parish house property, which is zoned residential and located in a historic district, and that the town of Hingham has asked about buying a piece of the land that abuts the town-owned senior housing Lincoln School Apartments.

Old Ship’s original parish house, which was torn down, was located farther down Main Street, where there is now a drive-in teller at Hingham Institution for Savings.

Johanna Seltz can be reached at seltzjohanna@gmail.com.