Bojnice castle stands on a massive travertine mound. The cave that is below the castle contains pools of fresh water. One of these pools is the source for a 26m-deep well that opens in the fourth courtyard. According to legend, a secret tunnel began near the well and ended somewhere outside the town wall.

The first mention of the castle is from 1113. The castle and surrounding estate were originally held by the royal family. Later, the king would grant the property to important lords for their achievements and loyalty. The most famous owners and holders of the castle included Matúš Čák Trenčiansky, and the Noffry, Corvinus Zápoľský and Thurzo families.

In 1643, the castle was acquired by Pavol Pálffy, and the estate remained in his family for almost 300 years. Count Ján Františec Pálffy (1852–1908) was the last nobleman to own the property. Ján Pálffy was a great arts lover and collector of antiques, and at his direction, the castle underwent a great reconstruction. He sought to transform the castle—and his six other properties—in the style of the French Gothic castles with the slogan, “In memory of famous ancient times.” One of the most well-known artifacts from his collection is the Bojnice altar, created by the Italian painter Nardo di Cione in the middle of the 14th century.

Ján Pálffy left no heirs, and his vast wealth was the cause of disputes between his relatives, even though specific clauses in his will stated that the property was to be available to the public as a museum with all of the art collections intact. It was not until May of 1950, when I fire destroyed much of the castle, that a plan was quickly drafted to restore Bojnice castle and open it to the public. The castle has served as a museum since September 7, 1950.