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 ('postpipe') 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 will often define its corners and sides.

Packing stones are often present in postholes and it is not uncommon to encounter them dug in to earlier ditch features. If a post was purposefully removed, then the action of rocking it back and forth leaves tell-tale evidence in the profile of the posthole which archaeologists can recognise. Destruction of posts, and therefore buildings, through burning can also be recognised.