In archaeology a posthole is a cut feature used to hold a surface timber or stone. They are usually much deeper than they are wide although truncation may not make this apparent. Although the remains of the timber may survive most postholes are mainly recognisable as circular patches of darker earth when viewed in plan. Archaeologists can use their presence to plot the layout of former structures as the holes may define its corners and sides. Construction using postholes is known as earthfast or post in ground construction.

Parts of a posthole

Although a very common structure, and one of the most basic found in archaeology, correct interpretation relies on being able to tell the often subtle differences that distinguish the parts of the posthole. The components of an archaeological posthole are listed in order of creation and, in ideal circumstances, the reverse order of their excavation.

Posthole cut The cut that formed the hole. It is cut from the ground surface level at time of construction. The sides of the hole may be distorted by later pressure on the post [as in the left hand example of the image, or later disturbance. Only careful excavation will be able to distinguish between the original cut profile and any later distortion.