Vlattenhaus, Medieval castle ruins in Eynatten, Belgium.

Vlattenhaus is a castle ruin on a walled island in Eynatten, Raeren. The island, about 30 by 30 metres, is enclosed by quarry-stone walls with the lower courses of round towers at its corners. The present three-storey building on a square plan combines a rough grey stone base with a large glazed upper section and a rounded turret-like projection at the front left.

Peter of Eynatten built the Vlattenhaus in the second half of the 14th century on the site of a former farmstead. In 1434 the male line died out and the house passed by marriage to the Thoreil family, then in 1475 to the von Vlatten family. The Jesuits, who received it in 1728, replaced the medieval house with a smaller building in 1761. On 12 September 1944, bombs severely damaged the house during fighting between American and German troops, leaving it a half-ruin until its late-1990s conversion.

The house takes its name from the von Vlatten family, who acquired it through the marriage of Anna Thoreil to Heinrich I. von Vlatten and held it until the early 18th century. Because Heinrich and his descendants were hereditary cupbearers (Erbmundschenken) of the Duchy of Jülich, the estate was also called Schenkenhaus. Locals long knew it as the "Great House" to distinguish it from the neighbouring "Small House", Amstenrath.

The building is a private residence and cannot be visited; the grounds are not open to the public. It stands on Hauseter Straße in Eynatten, about 200 metres from Amstenrath Castle, so it can only be seen from the street. The walled island measures roughly 30 by 30 metres, with the lower courses of round corner towers still in place.

The farm buildings outside the walled island include one with wall anchors dated 1781, a detail visible from the approach. The island itself measures about 30 by 30 metres, and the bases of round towers remain at its four corners.