Karen Brewer

WHEN John D. Crimmins bought his wife and 13 children a summer home in Darien, Conn., in 1891, he did what any self-respecting successful Victorian businessman would do. He gave the house a name: Firwood.

The house, on Long Neck Point, was the family’s summer sanctuary and a place to which John D. — as his descendants refer to him — retreated on long weekends when he wasn’t running the construction company that helped create the New York City we know today.

As a developer, Mr. Crimmins built many hospitals and churches. But he made his mark with elevated railways, and also laid the first underground lines for telegraphs and telephones.

When he died, Mr. Crimmins left his property to his daughters. Several of them went on to rear their families on land subdivided from the original 15 acres.

“They were scattered around Long Neck Point, so it was covered by cousins,” said Bill Ewing, a Crimmins great-grandson.

Darien eventually evolved from a summer resort to a year-round suburb. Mr. Ewing’s mother, a Crimmins grandchild, brought up her nine children at Firwood, and she died there in September. Bowing to changing times and demographics that leave Crimmins descendants with families of at most three offspring each, her heirs have reluctantly put Firwood on the market for $16.75 million

“I’m heartbroken,” said Sheila Daley, Mr. Ewing’s sister. “But the house is too big and land values have gotten so that it’s not practical for any one of us to take it over.”

Ms. Daley lives in a nearby house that John D. originally built for the entertainment of his children, complete with a billiard room and a great room for other games.

The rambling main house, at 203 Long Neck Point Road, sits on 4.8 acres on Long Island Sound. It has 14 bedrooms, 9 full baths and 13 fireplaces.