Strijthagen Castle is the last intact illustrious estate within the city limits of Landgraaf. It's located in the "Strijthagerbeekdal" near the township Schaesberg.
The main building is at the bank of a pond which gets its water from the Strijthagerbeek. It was built in the 18th century at the location of an older castle. The main building's walls are made from so called "speklagen", meaning alternating layers of brick and marl, a building style quite common in Limburg. This style can also be seen at Castle De Bongard (Bocholtz) or the nearby ruins of Castle Schaesberg.
The castle complex further consists of the bailiff's residence, a front castle built in 1690 AD, a watermill (Strijthagermolen) en the coach-house. All these buildings are national monuments.
The main building, the bailiff's residence and the gate building all have a mansarde roof, which in Limburg can be seen as well at Castle Puth and Castle Raath.
During the 20th Century the castle suffered from serious mining damage, because of its location next to the State Mines Wilhelmina and Oranje Nassau II.
Around the castle a large recreation area is located (Mondo Verde theme park and Gaia Zoo).
The theme park went bankrupt in 2006, and at 25 April 2013 the city council of Landgraaf decided to buy the castle grounds.