Very subtly situated on Henley-Marlow road, it sits at the point where the Chilterns meet the River Thames. Better know now as "Danny, Champion of the World" territory, before Roal Dahl there was Sir Francis Dashwood, keeper of the "Hellfire Caves" - http://www.themodernantiquarian.com/browse.php?site_id=549 (it'll look neater when I figure out linking). Just to the south of this almost obliterated site is the infamous "Medmenham Abbey", where Dashwood would have parties-cum-rituals that involved almost the entire gentry and their genitals, and lasted for weeks. Baboons were also often in attendance.
As for the Camp, sadly very little remains, with the north-western corner being the last vestiges of the earthworks. But rejoice! The site is crowded with gorgeous trees, and seems safe enough for now, as long as the scrambler-crew don't overdo it ...
In the grounds of Robert Scott, esq. there is a strong and perfect Danish encampment in the form of a rude horse-shoe. In its circular part it is fortified by a double vallum; the front towards the Thames is defended by the high cliff.
A few years since some warlike instruments were found in making a walk round the rampart; but I have not had an opportunity of seeing them.
The place has been called by the country [people] the Danes Ditches, and has given the name of Danesfield to an elegant residence of Mr. Scott, who has improved the house and grounds with great taste.
From p835 of 'The History and Antiquities of the Hundred of Desborough', by Thomas Langley, 1797 (which can now be read on Google Books).