Ardenne Castle, Royal château in Houyet, Belgium

Ardenne Castle was a royal residence in Houyet featuring 140 guest rooms equipped with modern amenities such as electric lighting, running water, and telephones. The estate included its own railway station to serve arriving visitors.

Leopold I bought 708 hectares called "Terre d'Hardenne et de Férage" on 21 March 1837, built a rock tower in 1843 and extended a hunting lodge with two towers. Leopold II demolished his father's manor in 1874; Alphonse Balat's replacement was finished in 1891, and Elie Lainé laid out the gardens. The château burned down in 1968.

The château's hotel era drew guests with novelties: each of the 140 rooms had a bathroom, running water, electric lighting and a telephone. Belgium's first golf course was laid out on the estate, and the hotel had its own stop on railway line 166, the Halte royale d'Ardenne.

The château, its annexe and the rock tower are gone; only the Leopold Tower stands, on the grounds of the Royal Golf Club du Château Royal d'Ardenne. It serves as the golf club's clubhouse, so access follows the club's grounds rather than a museum visit. The site lies in Houyet, Namur Province, near the Lesse valley.

The château's 1897–98 annexe by architect Alban Chambon was called an annexe but was as sumptuous as the main building; every room had a bathroom, running water, electric lighting and a telephone. The estate also had its own stop on railway line 166, the Halte royale d'Ardenne, and Belgium's first golf course.