Bornem Castle, also known as the De Marnix de Sainte-Aldegonde Castle (Dutch: Kasteel van Bornem, or Kasteel de Marnix de Sainte-Aldegonde), is a country house, formerly a castle, located in Bornem, province of Antwerp, Belgium. Bornem Castle is situated at an elevation of 1 meters.
The building stands on the Oude Schelde, a tributary of the Scheldt. The earliest fortification on the site was of the 10th or 11th centuries and was intended to defend against the incursions of the Vikings. A later castle was built on the foundations of the older building in 1587 by the Spanish nobleman Pedro Coloma, 3rd Baron of Bornhem and lord of Bobadilla, a follower of Alexander Farnese. The property was afterwards leased by the family de Marnix de Sainte-Aldegonde, who became the outright owners in 1773.
The present house was built on the same site at the end of the 19th century to plans by Hendrik Beyaert, after the remains of the 16th century building had been demolished. It remains in ownership of the house Marnix de Sainte-Aldegonde, the current resident is John de Marnix de Sainte-Aldegonde, 14th Earl of Bornem.
Coordinates: 51°06′10″N 4°13′00″E / 51.1029°N 4.2167°E