Holmbury St. Mary is located inside the Hurtwood Forest, which is considered the largest area of common land in Surrey; it takes up part of the Greensand Ridge which in turn contributes to the Surrey Hills AONB. Nearby to the south is Holmbury Hill, which at 857 feet (261 m) is the fourth highest point in Surrey. The summit of Holmbury Hill, containing the hill fort and Bray family memorial cairn, is the only part of the hill to be located in Holmbury, at the Ockley Estate.