The remains of an Iron Age promontory hill fort, Maiden Castle, are located on the southernmost summit of the southerly hill at an elevation of 212 metres. Maiden Castle dates from around 600 BC and is the most southerly of the seven hill forts in Cheshire. The double line of earth ramparts are still visible, forming a semicircle that encloses an area of adjacent to the cliff edge. The enclosure has a single entrance at the east side with inturned defensive banks. Archaeological investigations have shown that both ramparts are strengthened by dry stone walling; the inner rampart also has timber strapping. The fort was destroyed by fire in around 400 BC, although the area was probably used as a settlement until the Roman invasion of Britain in the 1st century AD.