A tiny island 60mi (97km) or so up the Hudson River from New York City is the setting for the ruins of Bannerman Castle. Built in the early 20th century as an arsenal by Scottish-American munitions merchant Francis Bannerman, the castle was designed to resemble Medieval Scottish fortresses. Following Bannerman's death in 1918, the structure fell into disrepair, with much of it destroyed by a fire that broke out in 1969. Today, Bannerman Castle Trust oversees the island and offers summertime island tours. It also hosts events, including barbecue picnics and concerts. Would you like to attend a summertime BBQ and concert here?

On the edge of the Hudson River in Tarrytown, New York, the Lyndhurst Mansion is the creation of acclaimed architect Alexander Jackson Davis, who built it in 1838. The Gothic Revival building is one of the finest castles in America and has had several noteworthy residents since its construction, including New York City mayor William S Paulding Jr and railroad tycoon Jay Gould. Tours of the mansion – including its art gallery, home to paintings such as The Madonna of the Roses by French artist William-Adolphe Bouguereau – are available on Fridays and weekends. Have you ever visited the Lyndhurst Mansion?

Though built in the early 20th century, Thornewood Castle – on the edges of American Lake in Lakewood, Washington – dates back much further. Chester Thorne, a prominent local banker and developer, dreamed of building a Tudor Gothic home, and after buying a 400-year-old English manor, he had it painstakingly dismantled, transported and reconstructed with the help of architect Kirtland Kelsey Cutter. Now an inn, Thornewood Castle offers guests access to the estate's private dock and lakeside beach and the beautiful sunken "secret garden" designed by the famous Olmsted Brothers, sons of Frederick Law Olmsted. Would you visit Thornewood Castle if you had the opportunity to?

Inspired by his time living in England as a child and falling in love with the castles in the area, American inventor John Hays Hammond Jr built the beautiful Hammond Castle between 1926 and 1929 to act as his home and laboratory. Constructed from a mix of local stone and various Roman, Medieval and Renaissance artefacts Hammond had collected during his travels to Europe, the castle overlooks the scenic Gloucester Harbor in Massachusetts and is now a museum. Today, you can tour its enchanting rooms, such as the unique inner courtyard partly made from Medieval storefronts that Hammond found on a trip to France and brought back to the US. Have you ever visited Hammond Castle?