Cholesbury Camp is a large and well-preserved Iron Age hill fort on the northern edge of the village of Cholesbury in Buckinghamshire, England. It is roughly oval-shaped and covers an area, including ramparts, of 15 acres (6.1 ha), and measures approximately 310 m (1,020 ft) north-east to south-west by 230 m (750 ft) north-west to south-east. The interior is a fairly level plateau which has been in agricultural use since the medieval period. The hill fort is now a scheduled ancient monument.
The fort is of the multivallate type, in other words having two or more lines of concentric earthworks. Most examples of such forts were built and used during the British Iron Age period between the 6th century BC and the Roman invasion of Britain in the 1st century AD. The period of Cholesbury Camp's construction is unclear, but it has been suggested that it may lie between the 2nd and 1st centuries BC, during the middle to late Iron Age. It was previously, though erroneously, attributed to the Danes and until the early 20th century was known locally as "The Danish Camp" and incorrectly recorded as such on maps. It has also been suggested that it may have been constructed on the same site as an earlier, Bronze Age defensive structure.
The fort is located in the Chiltern Hills at an altitude of over 190 m (620 ft). 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.