12 Awe-Inspiring American Castles!

There were 300 stonemasons, carpenters, and artists hired to build Boldt Castle, which was decorated with Italian marble, French silks, and Oriental rugs.

'Iolani in Honolulu, Hawaii, is America's only true palace—as in, royalty resided here. It was built from 1879 to 1882 by King Kalakua and Queen Kapi'olani.

'Iolani Palace includes a throne room (pictured), grand hall, and private suites, including the upstairs room where the queen was imprisoned for five months following the 1895 coup.

The 115-room Hearst Castle in San Simeon, California, was inspired by a Spanish cathedral and is set on 250,000 acres with 13 miles of coastline.

The Neptune pool at Hearst Castle has an authentic Roman temple pediment.

OHEKA Castle was built in Long Island in 1919 by millionaire financier Otto Herman Kahn, the inspiration for Mr. Monopoly.

OHEKA Castle ended up abandoned in the late 1970s and sustained extensive damage from fires, vandals, and neglect. After a 20-year renovation, it is now a 32-room luxury hotel.

It took 14 years to construct Castello di Amorosa in California's Napa Valley using historically accurate medieval building techniques.

Some 8,000 tons of Napa Valley stone was hand-chiseled to create Castello di Amorosa.

Like a modern-day Frankenstein's castle on Massachusetts's rocky Atlantic shore, Hammond Castle served as both home and laboratory for prolific inventor John Hayes Hammond Jr.

Located in Bucks County, Pennsylvania, Fonthill Castle—a mishmash of medieval, Gothic, and Byzantine styles—turns 100 in 2012.

Thousands of handcrafted ceramic tiles were inset throughout Fonthill Castle, including Persian, Chinese, Spanish, and Dutch productions.

A 400-year-old Elizabethan manor house was dismantled brick-by-brick and shipped round Cape Horn to be incorporated into Thornewood Castle, which is located near Tacoma, Washington.

The 54-room Thornewood Castle is now a hotel filled with antiques and artwork.

Of all the Gilded Age Victorians built along the Gulf Coast in Galveston, Texas, the Bishop's Palace remains the grandest—and not just because its steel and stone hulk survived the Great Storm of 1900.

The 14-foot coffered ceilings, 40-foot octagonal mahogany stairwell, stained glass, plaster carvings, and Sienna marble columns of the Bishop's Palace exude richness.

The exterior of Connecticut's Gillette Castle is made from local fieldstone and has medieval features.

Gillette Castle was designed by actor William Hooker Gillette, who was famous for playing Sherlock Holmes on the stage. 

Grey Towers Castle, outside Philadelphia, was built by eclectic sugar refiner William Welsh Harrison between 1893 and 1898 and is now part of Arcadia University.

Grey Towers Castle is now home to dorms and offices for Arcadia University, but the original features like hand-carved walnut and mahogany woodwork have been preserved.

New Hampshire's Castle in the Clouds was built on the rim of an extinct caldera high in the Ossipee Mountains, with unbroken views over 6,300 private acres of woods and lakes.

Castle in the Clouds is practically minuscule compared to the other castles on this list—there are only 16 rooms.