Sea Brows (milefortlet 23), 500m south west of Bank End part of the Roman frontier defences along the Cumbrian coast


Heritage Category:
Scheduled Monument
List Entry Number:
Date first listed:


Ordnance survey map of Sea Brows (milefortlet 23), 500m south west of Bank End part of the Roman frontier defences along the Cumbrian coast
© Crown Copyright and database right 2019. 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.

Allerdale (District Authority)
National Grid Reference:
NY 04471 37995

Reasons for Designation

Hadrian's Wall marks one of the frontiers of the Roman Empire. The international importance of the surviving remains has been recognised through designation as a World Heritage Site. The military importance of the Tyne-Solway route across the Pennines was recognised by the Romans in the second half of the first century AD when a military road, the Stanegate, was constructed along with a series of forts. There is evidence that the Tyne-Solway route was being recognised as a frontier by the start of the second century AD, but the line was consolidated in the early second century AD by the construction of a substantial frontier work, Hadrian's Wall, in c.120 AD. Subsequent attempts to establish the boundary further north, between Clyde and Forth, failed by c.160 AD. Hadrian's Wall then remained the frontier of the Roman Empire in Britain until c.400 AD when Roman armies withdrew from Britain. For most of its course, the 70 miles of Hadrian's Wall running from coast to coast comprised a continuous stone wall (which in places was first temporarily built of turf) with permanent structures sited at intervals of one Roman mile (milecastles) and at third of a mile intervals (turrets) between the milecastles. At a later date, the Wall was strengthened by 16 full-size garrison forts built either on, or close to, the Wall. To the north of the Wall, for most of its length, lay a substantial defensive ditch and to the south a complex of banks and ditches provided east-west communication and demarcated the frontier zone from the province. To the west of Bowness-on-Solway, where the Wall reached the sea, however, the frontier had a different character and served a slightly different purpose. At the western end of the Wall a system of milefortlets and towers, spaced similarly to the milecastles and turrets along the Wall, extended the frontier system for at least 27 miles down the Cumbrian coast and helped control movement across the estuary of the Solway Firth. In places these milefortlets and towers were supplemented by lengths of palisade fences. Throughout its long history the Wall was not always well maintained. It was often neglected and sometimes overrun, but it remained in use until the late fourth century when a weak and divided Roman Empire finally withdrew its armies from the Wall and Britain. The frontier works along the Cumbrian coast survive as earthworks or buried archaeological remains, the latter sometimes visible on aerial photographs. They survive in this form largely as a result of the more ephemeral materials of which they were built (timber and turf instead of the stone of Hadrian's Wall land frontier) rather than because of poor survival of archaeological remains. Components of the coastal frontier which have surviving archaeological remains, whether visible or not, will generally be considered of national importance.

A combination of aerial photographs and geophysical survey have shown that buried remains of Sea Brows milefortlet 23 survive reasonably well. The monument will retain undisturbed archaeological deposits and will contribute to any further study of the Roman frontier defences along the Cumbrian coast.


The monument includes the buried remains of all but the western edge of Sea Brows milefortlet. Within the sequence of milefortlets along the Cumbrian coast this one has been identified as number 23. The milefortlet was originally of turf and timber construction and is located on the top of a prominent cliff north east of Maryport Roman fort. It was found by aerial photography which showed the outline of the broad ditch of a milefortlet with an entrance on the south east side. The north west side of the milefortlet has been destroyed by erosion to the cliff edge. In 1994 geophysical survey produced a clearer picture of the buried remains of the milefortlet; low resistance readings confirmed the location of the main ditch on all sides except the eroded north western side, with a break on the south east side confirming the site of a causeway across the ditch giving access into the milefortlet. Internally several high resistance readings are considered to be associated with a turf rampart, building wall lines and areas of building rubble. In addition to the main fortlet ditch the geophysical survey detected other internal ditches which may reflect sub-divisions within the fortlet or, alternatively, the existence of an earlier milefortlet which may have been suffering from erosion and was subsequently rebuilt a short distance further inland away from the cliff edge. Exact measurement of the milefortlet is impossible to obtain because of the loss of the western edge of the monument, but the geophysical survey indicates that the fortlet including its ditch measures c.47m north east-south west. A field dyke and all post and wire fences are excluded from the scheduling but the ground beneath these features is included.

MAP EXTRACT The site of the monument is shown on the attached map extract.


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

Legacy System number:
Legacy System:


Books and journals
Geophysical Surveys of Bradford, , Roman Defences of the Cumbrian Coast, (1994)
AP , Manchester University,
AP , Manchester University,
Cumbria SMR 16515 AP No 2007,15, Cumbria County Council, Maryport, (1979)
Cumbria SMR 16515 AP No 2007,16, Cumbria County Council, Maryport, (1979)
Cumbria SMR 16515 AP No 2007,28, Cumbria County Council, Maryport, (1979)
RCHME, Cumberland Coast Events Record, (1995)


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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