[2] It sits along the undulating Greensand Ridge, its summit being 805 feet (245 m) from the elevated and tightly clustered small village of Holmbury St. Mary which was traditionally part of Shere, 8 kilometres (5.0 mi) away.
The hard band of chert on which the hill fort sits gives it a prominence over the weald that may have served as an assertion of control and security over the trade routes through the area.
It is 3.2 kilometres (2.0 mi) west of Leith Hill, the highest point in Surrey at 294 metres (965 ft), separated by a deep ravine draining north and south.
The sedimentary sandstone bedrock of Holmbury Hill is part of the Hythe Beds, laid down in shallow seas approximately 113 to 126 million years ago in the Cretaceous Period.
Quarrying added significantly to the other principal economic activity taking place on the hill such as timber production, turf cutting and gathering bracken and heather.