A summit shaped by glaciation in West Fife, Carneil Hill rises to 130m (426 feet) immediately to the southeast of Oakley and a half-mile (1 km) west of Carnock. Much of its geology is a relatively soft limestone formation which has been protected from a passing glacier by a hard igneous intrusion, dating from around 300 million years ago, which underlies the steep northwestern slopes. Thus the distinctive wedge shape which indicates the direction of ice flow from the northwest. The top is marked by an Ordnance Survey triangulation pillar and there is a communication mast nearby, with disused limestone quarries on its southern slopes.
The hill is thought to have been the ancient stronghold of the Horestii tribe, with the discovery of an earthenware urn containing coins in 1776 and later cremated bones were found nearby in another urn. It is thought there was a battle nearby between the Horestii and the Romans, although some sources suggest the battle was a thousand years later involving Norse invaders.