in 1994, suggested that three polished axes deposited at the eastern side of the enclosure were there to mark a boundary, for example if the enclosure represented the eastern extent of the territorial control of the people who built it. A 2001 review of the areas enclosed by causewayed sites found three distinct groupings of sizes, the smallest group ranging from , and the median at about . Many of these smaller enclosures are in the upper Thames Valley, near rivers, and of the others, those at higher elevations like Combe Hill, often have a second causewayed ditch surrounding the first. Most causewayed enclosures are fairly close to circular in layout, but the inner enclosure at Combe Hill is somewhat elliptical, the long axis running east–west. The outer circuit is not as well-preserved as the inner circuit, but this may be because parts of it were levelled, perhaps during the Neolithic. Causewayed enclosures can be broadly grouped by the physical landscapes in which they lie. Combe Hill is one of a group that lie on high ground, and like many of this type, the enclosure is placed so that it is visible from the high ground near the site, but not from the lower ground from which the hill is most clearly visible. Combe Hill's enclosure slopes slightly away from the steep north slope, so that none of the earthworks can be seen from the north—instead, it is visible from the massif of the South Downs, to its south. However, given that Combe Hill was probably constructed when trees covered the area, the cleared area would have been visible from the north as a treeless notch, above the steep slope. A Neolithic enclosure (probably causewayed) at Butts Brow, about to the south of Combe Hill, was identified in 2016. The two sites are visible from each other, and dating evidence from pottery at Butts Brow makes it plausible that there was activity at both sites at the same time. Combe Hill was listed as a scheduled monument in 1981. Archaeological investigations The historian Hadrian Allcroft included the site in his 1908 survey, Earthwork of England; he describes it as of "almost beyond doubt of British construction", meaning that it precedes the Roman conquest. The plan he drew shows no gaps in the ditches and banks around the site, reflecting his belief (common among archaeologists at that time) that the gaps