The fort is located in the Chiltern Hills at an altitude of over . The porosity of the ground in the area severely limited the availability of surface water, essential for livestock, and therefore precluded year-round settlement adjacent to most of the upland pastures. However, there are two aquifer-fed water sources: Holy (or Holly) and Bury Ponds. The constancy of this supply, over many hundreds of years, is cited as being crucial to the decision as to where to site the hill fort and for the early establishment of the isolated community at Cholesbury.