A 22-room Neoclassical mansion in Pennsylvania that was built in 1921 and remains virtually untouched has hit the market for $2.15 million.

The extraordinary property, which is located in Wallingford, was originally designed for industrialist Howard H. Houston, for whom it is now named—and, while it has been carefully updated in the years since its completion to bring it up to modern standards, its bones and design details still hark back to the same year of its build.

As a result, the six-bedroom estate, which is known as the Houstonia mansion, remains one of the finest surviving examples of the Neoclassical era of architecture.

“No detail was spared in this 22-room estate—you’ll find all of the grace and charm of the time period intact with tasteful and modern updates, making the home both a lovely endeavor in preserved history and well-suited for today’s discerning buyer,” the listing notes.

“With an incredible amount of original architectural elements whose quality in craftsmanship and detail is a rarity in today’s builds, the home is quintessentially Neoclassical.”

Listing agent Brooke Penders of Coldwell Banker Realty agrees, stating: “Houstonia is an exquisite example of Neoclassical design. It is astonishing that the home has been so beautifully preserved with exceptional care and detail.”

Widely considered a masterful architectural gem, the property’s impressive design begins with its regal facade and entryway, which is flanked by four large columns, while further design excellence awaits just through the front door.

A bluestone terrace with a Juliet balcony and two-story portico opens up to the primary estate.

“The main stairs in the entry hall are breathtaking, leading to a large Palladian window and then splitting into two curving stairways,” Penders noted. “The office features Houston’s original hand-painted safe built into a custom closet.”

Historic highlights found throughout the 7,569-square-foot interior include preserved hardwood floors, hand-carved millwork, custom wainscoting, pocket doors, and dual staircases.

A light-filled living room with a soapstone hearth fireplace has access to a nearby sunroom.

“This home is an ideal primary residence, superbly situated near the Philadelphia International Airport, and key commercial centers in Philadelphia, Wilmington, and more,” she said.

“At the same time, it offers easy access to many second-home markets for convenient recreational getaways like the New Jersey shore, Delaware beaches, Pocono mountains, and the Chesapeake Bay.”

Other amenities include a home office, a dining room with a second soapstone hearth fireplace, a gourmet chef’s kitchen with a butler’s pantry, and a spacious primary suite with a dressing room.

A guest suite can be found on the third floor, along with bonus rooms, walk-in cedar storage rooms, and a billiard room currently being used as a family room.

“Properties of this stature, in terms of design purity and integrity, as well as size of home and acreage, are exceptionally unusual within this school district and the surrounding area,” Penders said. “Homes such as this rarely come to market.”

The expansive lot also boasts a 2,500-square-foot detached carriage house with three heated garage bays located on a separately deeded parcel.

Designed for guest accommodations, multigenerational living, or additional rental income, the two-bedroom residence features a great room, eat-in kitchen, family room, and private deck.

“With an abundance of rooms and space, the property can easily accommodate a large or multigenerational family,” she said.

Penders believes the next buyer might be attracted to this area because of the highly rated school district along with its close proximity to major employment hubs.

“Set on five acres containing the Houstonia mansion, a three-car detached garage with two-bedroom apartment, a former greenhouse, and extensive lawns and woods, the property is bounded by township parks and Ridley Creek, further enhancing the privacy,” she said.