It’s something that we’ve all thought about at some point: If we had unlimited money, what sort of house would we build for ourselves, and where would we build it? For some people, that dream came true, and they ended up constructing huge houses that are opulent and ornate beyond our wildest dreams.
Driving down the street in a fancy neighborhood, you’ll encounter some truly jaw-dropping houses, owned by folks who make more money that most of us will ever see. These folks are wealthy, sure, but their wealth pales in comparison to the folks who built the largest mansions ever constructed in America.
Seriously, the scale of these mansions is simply jaw-dropping: The average square footage of a single-family house in the United States is about 2,000 square feet, and anything over 3,000 is considered pretty big. The White House clocks in at 55,000 square feet, for reference. But the smallest house in our ranking is 60,000 square feet, and the largest house in America is nearly three times that size.
As most of these mansions were built by Gilded Age industrialists and robber barons, it goes without saying that not many of them are still inhabited; most were donated to colleges or turned into museums. Some, however, are newly built private homes (and some are still under construction) owned by some of the wealthiest folks on the planet. Read on to learn all about the 21 largest houses in the country, based on square footage.
Whitehall was built by the renowned architectural firm Carrère and Hastings for railroad tycoon Henry Flagler, and was completed in 1902. Flagler is widely regarded as the man responsible for turning Florida into a tourist destination, and his mansion is one of the finest surviving examples of neoclassical Beaux Arts architecture. Today, it’s home to the Flagler Museum, and its 55 rooms, dripping with marble, gilding and murals, have all been meticulously restored.
Montgomery County Planning Commission
Designed by architect Horace Trumbauer and constructed between 1897 and 1900 for Philadelphia businessman Peter A.B. Widener, Lynnewood Hall contains 55 bedrooms, a massive art gallery (once home to one of the Gilded Age’s finest private art collections), a ballroom that could hold 1,000 guests, wine cellars and a swimming pool. Widener’s son and grandson died in the Titanic’s 1912 sinking, and Widener passed away three years later. The stately Indiana limestone mansion has sat largely vacant since the 1950s, but it remains the largest surviving Philadelphia-area Gilded Age mansion.
Built as the summer home of Cornelius Vanderbilt II in 1895 by renowned architect Richard Morris Hunt, The Breakers remains the crown jewel of Newport, and one of America’s finest surviving Gilded Age mansions. Built in the Italian Renaissance style on 14 acres overlooking the ocean, its Renaissance Revival style, well-groomed gardens and interiors rich with imported marble, mosaics, rare woods and other high-end architectural elements placed it among the most celebrated mansions of the era. Today, it’s a must-visit museum.
Mar-a-Lago was constructed in the Spanish Colonial Revival style from 1924 to 1927 for socialite and cereal heiress Marjorie Merriweather Post by architect Marion Sims Wyeth. The ornate mansion contains 58 bedrooms, 33 bathrooms and 12 fireplaces, and the 17-acre estate spans the entire width of Palm Beach, from the Atlantic to the Intracoastal Waterway (hence, the name, which translates to “Sea-to-Lake.” When Post died in 1973, she willed the estate to the federal government, which found the property too difficult to maintain. Donald Trump purchased the property in 1985 and turned it into a private club.
Built in 2003 for junk bond billionaire, philanthropist and major Republican donor Ira Rennert, Fair Field sits on a 63-acre estate, and all the buildings on the property add up to more than 110,000 square feet. The main house has 29 bedrooms, 39 bathrooms, 12 chimneys, a 91-foot formal dining room, a bowling alley, a basketball court and a $150,000 hot tub. Its construction was so controversial that writer James Brady wrote a novel about it, called “The House That Ate the Hamptons.”
This Tudor Revival style estate was constructed between 1912 and 1915 for Goodyear Tire co-founder F.A. Seiberling; its name roughly translates to “stone quarry” in Old English. Inspired by English country homes and decorated with Tudor antiques as well as contemporary (to 1915, at least) furnishings, the four-story mansion has a large music room, an indoor swimming pool and a formal dining room that can seat 40. It’s also nestled on 1,500 acres of landscaped grounds (one of the finest extant works by renowned landscape architect Warren H. Manning). It’s been fully restored, and tours are offered April to December.
You might have heard of the owners of this behemoth on the shores of Lake Washington: Microsoft founder and philanthropist Bill Gates and his wife Melinda. Designed by Bohlin Cywinski Jackson and Cutler-Anderson Architects in the Pacific lodge style and completed in 1995, the house was informally dubbed “Xanadu 2.0,” after Charles Foster Kane’s mansion in Citizen Kane. Constructed over the course of seven years at a price of $63 million, it contains six kitchens, seven bedrooms, 24 bathrooms, a 1,000-square-foot dining room, a 2,500-square-foot gym (with its own trampoline room), a 23-car garage, a reception hall for 200 people, a 20-seat movie theater, a library with a domed roof and oculus, a 1,900-square-foot guest house and a private beach with Caribbean sand. As can be expected from Gates, the house is chock-full of super high-end technology, including a private sewer system, wearable pins that let each guest control the lighting and temperature in a room (pretty cutting-edge in 1995), and a 60-foot indoor-outdoor swimming pool with an underwater music system.
Photo Courtesy Arcadia University
Grey Towers was constructed in 1893 as the estate of sugar magnate William Welsh Harrison, and was designed by famed Gilded Age architect Horace Trumbauer. The grey stone castle’s exterior is Gothic Revival, but the interior architectural style is primarily French Renaissance, with giant mantles and a barrel-vaulted, gilded ceiling in the great hall and large tapestries throughout. The building was sold to what’s now Arcadia University after Harrison’s passing in the late 1920s, and it remains the beloved centerpiece of the school today.
This Spanish Colonial Revival masterpiece was constructed between 1919 and 1947 for publisher William Randolph Hearst, and was designed by one of America’s first major female architects, Julia Morgan. Hearst entertained all the biggest celebrities of the day here in the ‘20s and ‘30s, and the entire complex is actually comprised of the massive Casa Grande (with its famous bell towers modeled after a church in Ronda, Spain) as well as three sprawling guest houses, elaborate gardens and the 345,000-gallon Neptune Pool, which has been called the most beautiful swimming pool on Earth. Hearst spared no expense in its construction, and filled it to the brim with a massive collection of antiquities, sculptures, tapestries and paintings. This is up there with America’s most famous castles for a good reason: It’s absolutely spectacular, inside and out. Today, it’s owned by the State of California, and is open to visitors.
Designed by McKim, Mead & White in the Italian Renaissance Revival style for the Vanderbilt family and completed in 1895, Woodlea has sweeping views of the Hudson River, an exterior bursting with Beaux Arts details, and a restrained yet elegant interior with plenty of marble, coffered ceilings, wainscoting and parquet floors. The mansion itself has 140 rooms total, including three banquet halls and bedrooms that were each designed in different architectural styles. In 1911, the mansion became the clubhouse of the 338-acre Sleepy Hollow Country Club (one of America’s top golf clubs), and Woodlea today is primarily used as a (very upscale) venue for private events.
Photo Courtesy Ed Dertinger
Designed by Richard Rowling Hunt in the English Country style for William K. Vanderbilt and completed in 1901, Idle Hour was the centerpiece of a 900-acre estate on Long Island’s Connetquot River. Built with red brick and connected by a covered cloister to a palm garden, guest wing and indoor tennis court, the main house was regarded as one of Long Island’s most splendid upon its construction. After Vanderbilt’s death in 1920, the estate was subdivided, and eventually it made its way into the hands of Dowling College, which owned it until the school shut down in 2016. The building’s future remains up in the air, but thankfully it was landmarked in 2018.
As far as houses go, Pensmore is certainly unique. Steven T. Huff made his fortune by founding several companies in the defense intelligence industry, and after selling those companies he decided to build a home in the Ozarks that would withstand tornadoes, earthquakes and bomb blasts. Made of insulated concrete and with 12-inch-thick walls, the five-story house has 13 bedrooms and 14 bathrooms, and even though construction began in 2008, the house still isn’t fully completed.
Lessing's Hospitality Group
This mansion was designed by renowned architect Ernest Flagg for Singer Sewing Machine Company president Frederick Gilbert Bourne, and was completed in 1897. In 1926, it was sold and became the La Salle Military Academy, and it was later used as a campus of St. John’s University. It was leased by Lessing’s Hospitality Group in 2002, and after a thorough renovation and restoration, it re-opened as one of Long Island’s top event venues.
The McKim, Mead & White masterpiece Florham was built as the country estate for Florence Adele Vanderbilt (Cornelius Vanderbilt’s favorite grandchild) and her husband, Hamilton McKown Twombly, and construction was completed in 1899. Inspired by Christopher Wren’s Hampton Court Palace expansion, the mansion was as lavish as you’d expect from the Vanderbilts: 110 rooms, interior design by Stanford White, gardens designed by Frederick Law Olmsted (the genius behind New York’s Central Park), Barberini tapestries, imported Renaissance-era fireplaces, a Louis XV-style ballroom, an orangery and a heating system designed by Thomas Edison himself. Florence lived there until her death in 1952, and the estate was broken up and sold in 1955 (many of the interior furnishings were gifted to the White House, and some remain there today). In 1967, the mansion and 178 acres of land were sold to Fairleigh Dickinson University, and today Florham is the crown jewel of its Madison campus.
Orlando Sentinel/ TNS
David Siegel, the founder of timeshare company Westgate Resorts, is currently building one of the most outrageous houses ever constructed. Along with his wife, socialite Jackie Siegel, they’re constructing what they’ve dubbed a modern-day Versailles, with 14 bedrooms, 32 bathrooms, 11 kitchens, a bowling alley, a roller rink, five pools (three indoor and two outdoor), a 1,000-person ballroom, a two-story movie theater inspired by the Paris Opera, a gym and 10,000 square foot spa, an aquarium, a yoga studio and a 20,000-bottle wine cellar. Outside, there will be a formal garden, a baseball diamond and two tennis courts. Construction hasn’t exactly been a breeze, though; it stalled in 2009 as the financial downturn hit, but picked back up again in 2013. It’s still not completed, but the final price tag is expected to top $100 million.
Theresa Finck/Meadow Brook Hall
Constructed in the Tudor Revival style between 1926 and 1929 for Matilda Dodge Wilson (the widow of Dodge motor car company founder John Francis Dodge) and her second husband, Alfred G. Wilson, Meadow Brook Hall was designed by the firm of Smith, Hinchman & Grylls and boasted 110 rooms. Alfred and Matilda lived there until their deaths in 1962 and 1967, respectively, and donated the entire estate (which encompassed 1,500 acres) to Michigan State University in 1957, along with $2 million to create a branch of the college. Today, it’s called Oakland University, and Meadow Brook Hall remains its centerpiece. The grounds of Meadow Brook Hall also hosted the Concours d’Elegance collector car show annually from 1979 to 2010.
Shadow Lawn was constructed in 1927 for the president of the Woolworth company, a man named Hubert Parsons, on the site of an earlier mansion that served as President Woodrow Wilson’s “summer White House” before burning down. Parsons was ruined by the Great Depression, however, and he ended up selling the 130-room building in 1939 for a paltry $100. In 1956 Shadow Lawn became part of Monmouth University, and today it’s known as Woodrow Wilson Hall. Fun fact: Shadow Lawn was used as Daddy Warbucks’ mansion in the 1982 film “Annie.”
Built around the turn of the 20th century by Henry Francis du Pont and his father, Henry Algernon du Pont, in the style of an 18th-century European country house, over the next 30-odd years Winterthur increased in size nearly sixfold as Henry Francis continued to add to it. The estate was largely constructed to hold H.F.’s massive collection of American art and decorative arts as well as conservation laboratories, and in 1951 he actually moved out of the main house and into a smaller “cottage” on the 979-acre estate. Today, its 175 rooms house 85,000 objects dating as far back as the 1600s (it’s one of the finest extant collections of American fine art, furniture and manuscripts) as well as research and conservation facilities, and most of the mansion is open to the public.
Photo Courtesy Peter Bond
Designed by the renowned architectural firm of Carrère and Hastings for railroad magnate Edward Henry Harriman and his wife, Mary, Arden was the main house of an estate comprising more than 30 square miles. Construction wrapped up in 1909, but sadly Harriman was only able to live in the house for a few months before passing away. It was Gilded Age luxury and ostentatiousness at its finest, complete with a music room in the style of a medieval great hall and commissioned murals, sculptures and tapestries by some of the greatest artists of the era. The house was given to the U.S. Navy during World War II, when it became the Navy’s first convalescent hospital. In the 1950s it became what’s regarded as America’s first conference center.
Oheka Castle was built as the country home of investment financier Otto Hermann Kahn, constructed by Delano and Aldrich in the Chateauesque style between 1914 and 1919 (the name is a portmanteau of Kahn’s first, middle and last names). One of only two once-private homes in the U.S. to clock in at more than 100,000 square feet, it contains 127 rooms and was once part of a 443-acre estate. After Kahn died in 1934, it passed through several owners before being taken over by the Eastern Military Academy, which promptly bulldozed the formal French garden and subdivided the mansion’s rooms. After the school closed in 1979 the house fell into a state of total disrepair, and nearly burned down several times. In 1984, however, it was purchased by Long Island developer Gary Melius, who restored the house and grounds in one of the largest residential restoration projects in U.S. history, and today it’s one of the country’s most high-end wedding venues; it’s also a luxury hotel and conference center.
The Biltmore Estate isn’t just the largest privately-owned house in the United States; it blows the competition out of the water. Built in the style of the finest French chateaux by renowned architect Richard Morris Hunt between 1889 and 1985 for George Washington Vanderbilt II (who dubbed it his “little mountain escape”), the mansion boasts 35 bedrooms, 43 bathrooms, 65 fireplaces, three kitchens and a grand total of four acres of floor space, as well as cutting-edge (for the time) innovations like forced-air heating, fire alarms, a call-bell system, centrally-controlled clocks and electric elevators. The construction project was so massive that a woodworking factory and a brick kiln had to be constructed on site, and a 6-mile railroad spur was built to bring materials to the site; more than 1,000 workers labored to construct it. Its interiors are about as lavish as you’d expect: For example, the Banquet Hall, the house’s largest room, has a 70-foot-tall barrel-vaulted ceiling, the table could seat 64 guests, and rare Flemish tapestries and a triple fireplace line the walls. Oh, and Frederick Law Olmstead designed the 125,000-acre grounds, the driveway alone is 3 miles long, and a planned town modeled after a quaint English country village was built nearby to house workers.
Today, the estate encompasses 8,000 acres and is overseen by a family trust called the Biltmore Company, and Biltmore Village is one of Asheville’s most charming neighborhoods (although the house itself is not an official part of any town). The fully restored house welcomes 1.4 million visitors every year, and is one of the most spectacular tourist attractions in the country.
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