Frederiksborg Castle is a historic castle located in Hillerød, Denmark, north of Copenhagen. It was built in the early 17th century by Christian IV as a residence for the royal family. The castle is situated on three small islands in the middle of a lake and is surrounded by a large formal garden.

The castle has been used as a royal residence, as well as a museum of national history since 1878. The museum contains a collection of paintings, sculptures, and decorative arts from the 16th to the 19th century, including works by Danish and Dutch masters.

The castle was severely damaged by a fire in 1859, but was restored and reopened to the public in 1878. Today, visitors can tour the castle's many rooms and halls, including the Great Hall, the Chapel, and the Knights' Hall, which features 17th-century tapestries depicting the history of Denmark.

In addition to its impressive architecture and art collection, Frederiksborg Castle is also renowned for its beautiful gardens, which feature fountains, sculptures, and a large lake. Visitors can explore the castle's formal gardens, which are divided into several sections, including a rose garden, an English-style garden, and a baroque garden.