Three rectangular defended enclosures 460m north east of Merthen Manor


Heritage Category:
Scheduled Monument
List Entry Number:
Date first listed:
Location Description:
Legacy Record - This information may be included in the List Entry Details.


© Crown Copyright and database right 2021. All rights reserved. Ordnance Survey Licence number 100024900.
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The building or site itself may lie within the boundary of more than one authority.

Location Description:
Legacy Record - This information may be included in the List Entry Details.
Cornwall (Unitary Authority)
National Grid Reference:
SW 73078 26655

Reasons for Designation

Defended enclosures are discrete plots of land enclosed by stone walls or banks of stone and earth sometimes with an outer ditch, which may date from the Bronze Age (c.2000-700 BC) or later. They were constructed as stock pens or as protected areas for crop growing and were sometimes subdivided to accommodate stock and hut circle dwellings for farmers and herdsmen. The size and form of enclosures may therefore vary considerably depending on their particular function. Their variation in form, longevity and relationship to other monument classes provide important information on the diversity of social organisation, farming and trading practices. The three rectangular defended enclosures 460m north east of Merthen Manor are unusual and seem to be linked with both agriculture and trade as well as having a defensive importance. They will contain archaeological and environmental evidence relating to their construction, function, date, relative chronology, adaptive re-use, agricultural practices, trading links, social organisation, territorial significance, domestic arrangements and overall landscape context. There are similar enclosures in the area apparently related to the navigable significance of the Helford River.


The monument includes three rectangular enclosures, known locally as Merthen Camp, situated on the upper slopes of a spur into the Helford River which terminates at Groyne Point. The two southern enclosures survive as separate, but closely-spaced rectangular central areas defined by outer banks of up to 1.3m high and partially buried ditches which measure up to 2m deep. The eastern enclosure of the two measures approximately 100m long by 85m wide. It has a central entrance on the north side and a double bank and ditch on the south side. The western enclosure measures approximately 100m long by 65m wide and has a single slightly off centre entrance on its north side. The northern enclosure survives as a slight, ploughed-out bank of stonier material enclosing an area measuring 46m north to south by 100m east to west. There is a possible entrance on the western side.

The enclosures lie within the old deer park at Merthen. The name Merthen is derived from the Cornish 'merthyn', meaning sea fort, and its use was first documented in 1186. The enclosures were first recorded by Thomas in 1842 and plotted on the 1907 Ordnance Survey map. They were fully described by Henderson who noted an ancient track from Merthen Quay passed along the west side of the enclosures going towards Rame the tin producing area locally. Harvey used this evidence to suggest Merthen Camp was a possible Roman customs post, and it has been compared to Carvossa, a Romano British trading post on the upper reaches of the Fal estuary. Although the exact date of the enclosures is unknown, they are believed to be largely contemporary with the south eastern one having been constructed first.

Sources: HER:- PastScape Monument No:-427118


The contents of this record have been generated from a legacy data system.

Legacy System number:
CO 183
Legacy System:


This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Digital, Culture, Media and Sport.

End of official listing

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