| Castercliff | |
| Map Type: | United Kingdom Borough of Pendle |
| Coordinates: | 53.8417°N -2.1823°W |
| Location: | Pendle, Lancashire, England |
| Type: | Hillfort |
| Length: | 115m (377feet) |
| Width: | 76m (249feet) |
| Area: | 0.8ha |
| Height: | 1.5m (04.9feet) |
| Built: | 510±70 BC |
| Excavations: | 1971 |
| Designation1: | Scheduled Ancient Monument |
| Designation1 Offname: | Castercliff Small Multivallate Hillfort |
| Designation1 Number: | 45247 |
Castercliff is an Iron Age multivallate hillfort situated close to the towns of Nelson and Colne in Lancashire, Northern England.
__TOC__It is located on a hilltop overlooking the valley system of the River Calder and its tributaries, on the western edge of the South Pennines. On the upper part of the hill, triple rubble ramparts up to high, separated by ditches of similar depth, surround the site on all sides except the north. On this side the defences consist mainly of a single rampart and ditch, but some short lengths of triple rampart and ditch are also found here. The inner rampart may have been timber-laced and revetted with stone and enclosed an oval area measuring approximately 115by.
The summit of the hill is 920feet above sea level and the surrounding ground falls rapidly on all sides except the south east. Here a neck of land, dropping 60feet from the summit, connects it to similarly high ground about NaN400 away. Streams spring from either side of the ridge and the deep valleys which they have cut, especially on the south, offer additional defence.
Excavations during the 1970s appear to show that the site was not completed, and no evidence of occupation was unearthed.[1] However, in the past, evidence of Roman occupation has been found and in 1898, Harry Speight was in no doubt that the site was the Roman Colonio.[2] The site is a Scheduled Ancient Monument.[3] The hillfort has been damaged by coal mining with old bell pits evident both inside and around the site.