A Vanderbilt estate in the Berkshires has hit the market for $12.5 million. See inside.

Buying Luxury
The estate has 46 bedrooms and 27 bathrooms and sits on 89 acres. Gavin Preuss

A piece of the Berkshires’ Gilded Age has hit the market for $12,900,000.

Elm Court, once known as the country estate of the Vanderbilt family, is so expansive that it’s located in both Stockbridge and Lenox. Spanning 89 acres, the property is emblematic of the Berkshires’ storied history as a playground for uber-wealthy industrialists looking for peace and quiet in the countryside during post-Civil War America. As they prospered financially, dynasties like the Carnegie, Choate, and Westinghouse families sought refuge in Western Massachusetts, where they could live lives of grandeur in a bucolic setting.

Built in 1886 as a “summer cottage,” Elm Court was owned by William Douglas Sloane and Emily Thorn Vanderbilt, granddaughter of family patriarch Cornelius Vanderbilt. Of course, the mansion qualifies as a “summer cottage” in a way that applies only to Gilded Age industrialists who owned gargantuan vacation estates. Known as one of the largest American Shingle-style homes in the United States, the home has a design completed in subsequent years by famed Boston architects Peabody & Stearns, while Frederick Law Olmsted created the rolling gardens and landscaping.

“The detail that it was created with is remarkable,” said Timothy Lovett of Berkshire Property Agents, who has the listing. “Evidently, it was a large house when it was built, but it grew and grew when she [Emily] would come and stay for the summer.  She’d find other things she wanted to do, so renovations went on for a 15-year period.”

Tucked behind gates, the estate offers nearly 55,000 square feet living space and has 46 bedrooms and 27 bathrooms. It features gardener’s and butler’s cottages, a carriage house and stable, greenhouses, and two barns. While elements of the estate are in dire need of renovations, several touches will fascinate any Gilded Age enthusiast, such as the fountain that’s a replica of the Fontana delle Tartarughe in Rome, and the cistern by the lily pond, where servants used to pump and filter water to be brought up to the main house. Mercury glass doorknobs can be spotted throughout, as well as coffered ceilings and wood-burning fireplaces.

In addition to its place in the Vanderbilt family’s history, Elm Court also plays a role in American history. In 1919, the Elm Court Talks held at the home would shape the creation of The Treaty of Versailles and League of Nations. Now listed on the National Register of Historic Places, the home became an inn by the 1940s but eventually closed and fell into disrepair. For years, vandals ransacked the once-luxe features. But by 1999, members of the Vanderbilt family had overhauled the property, restoring sections to its former glory.

While plans to turn Elm Court into a resort were scrapped earlier this year, the current owners are hoping a buyer will want to embrace its storied past.

“We don’t see that level of craftsmanship anymore,” Lovett said.

See more photos of the estate below:

Subscribe to the Globe’s free real estate newsletter — our weekly digest on buying, selling, and design — at Follow us on Facebook, Instagram, and Twitter @globehomes.