The park was designed in the style of an English landscape garden by Phillip August von Briest around 1780. It is characterised by wonderful old oaks, a historic tree population and a picturesque aquatic landscape of ponds, ditches and adjacent wetlands. It is considered one of the earliest landscape parks in Brandenburg. Caroline (1775-1831), the only daughter of August Phillip von Briest, married the romantic poet Friedrich de la Motte Fouqué (1777-1843) in 1803. She lived with him in Nennhausen for 30 years. Fouqué wrote his famous art fairy tale "Undine” here, which is regarded as the model for Hans Christian Andersen's "The Little Mermaid" and Walt Disney's "Arielle". The stimulating hospitality of the Fouqués, the poet’s rum and the importance of many visitors, including Adalbert von Chamisso, E.T.A. Hoffmann and Wilhelm von Humboldt, A.W. Schlegel, among others, gave Nennhausen the reputation of a "Brandenburg Mark Home of Muses” (Günter de Bruyn). Visitors will meet many of these personalities as they stroll through the park, in the form of ceramic medallions with portraits and quotations, an “Undine” rising from the water and another character, “Effi Briest”, swinging on a tree swing. The landscape park and Nennhausen Castle are privately owned.
The manor house – Nennhausen Castle - regularly hosts events, such as concerts and readings. A conference room and registry office room is located on the ground floor of the Orangery of the park with a terrace overlooking the park. It is suitable for smaller parties, meetings and exhibitions. A spacious holiday apartment is located on the upper floor of the Orangery.