Astrid Gräfin von Hardenberg
Born in Potsdam, von Hardenberg started studying in 1942 at the Berlin State School but was forced to interrupt her studies in 1943, in order to work as Red Cross nurse in different hospitals, among which the military hospital in Rosenheim. In July 1944 the family mansion was confiscated because of the family's involvement in the 20 July plot against Hitler. She worked till 1990 for the European Commission in Brussels.
After the German reunification, Friedrich Karl Graf von Hardenberg requested the restitution of the family property as Carl-Hans von Hardenberg's son and legal heir. Because of his old age, he bequeathed the property to his sister Astrid and his nephew Gebhard. The request was approved in 1993 and the von Hardenberg family took possession of the estate in Neuhardenberg in 1996.
The mansion and the park were sold to the Deutscher Sparkassen und Giroverband which started the restoration the following year. The mansion's park was redesigned and the memorial for Frederick II of Prussia was also rehabilitated. The new owner developed the mansion as an international cultural center and created the "Schloss Neuhardenberg Foundation". The von Hardenberg family kept the Lietzen commandry (Komturei) and the Neuhardenberg estate.
In 1998, Astrid von Hardenberg created the Carl-Hans von Hardenberg Foundation in memory of her father. The foundation promotes the education of young people from the Märkisch-Oderland Kreis (district) and from the neighboring areas, including those beyond the German-Polish border. It also promotes social involvement and creativity of young people. The foundation emphasizes Christian orientation of youth activities and cross-border exchanges of young people.
Astrid von Hardenberg died in Berlin on 4 February 2015, aged 89.
- Regarding personal names: Gräfin was a title before 1919, but now is regarded as part of the surname. It is translated as Countess. Before the August 1919 abolition of nobility as a legal class, titles preceded the full name when given (Graf Helmuth James von Moltke). Since 1919, these titles, along with any nobiliary prefix (von, zu, etc.), can be used, but are regarded as a dependent part of the surname, and thus come after any given names (Helmuth James Graf von Moltke). Titles and all dependent parts of surnames are ignored in alphabetical sorting. The masculine form is Graf.
- Profile[permanent dead link], wwwarc.eui.eu; accessed 24 February 2015.
- Maja Prinzessin von Hohenzollern - Mit den Hardenbergs kam die Hoffnung nach Lietzen 
- Stiftung Schloss Neuhardenberg
- Opfergang für die Nation. Astrid Gräfin von Hardenberg über den Patriotismus des 20. Juli 1944 und den Kampf ihres Vaters für Deutschland, jf-archiv.de; accessed 24 February 2015. (in German)
- Carl-Hans von Hardenberg Stiftung profile, hardenberg-stiftung.org; accessed 24 February 2015.
- Rosarium infosite, welt-der-rosen.de; accessed 24 February 2015.
- "Astrid Gräfin von Hardenberg mit 89 Jahren gestorben" (in German). Berliner Morganpost. 10 February 2015. Retrieved 19 February 2015.