Iron Age territorial boundary known as Beech Bottom Dyke


Heritage Category:
Scheduled Monument
List Entry Number:
Date first listed:
Date of most recent amendment:


Ordnance survey map of Iron Age territorial boundary known as Beech Bottom Dyke
© Crown Copyright and database right 2019. All rights reserved. Ordnance Survey Licence number 100024900.
© British Crown and SeaZone Solutions Limited 2019. All rights reserved. Licence number 102006.006.
Use of this data is subject to Terms and Conditions.

The above map is for quick reference purposes only and may not be to scale. For a copy of the full scale map, please see the attached PDF - 1019136 .pdf

The PDF will be generated from our live systems and may take a few minutes to download depending on how busy our servers are. We apologise for this delay.

This copy shows the entry on 23-Jul-2019 at 05:44:33.


The building or site itself may lie within the boundary of more than one authority.

St. Albans (District Authority)
St. Albans (District Authority)
National Grid Reference:
TL 14793 08781, TL 15401 09012, TL 16033 09426

Reasons for Designation

The Iron Age territorial boundary known as Beech Bottom Dyke, forms a major component of the late Iron Age landscape surrounding the important nucleated settlements near St Albans (Verlamion) and Wheathampstead. Verlamion is located on the western bank of the River Ver, within and to the south of Prae Wood and beneath and to the north of the later Roman town of Verulamium. Excavations have shown the site to have been the trading and administrative centre for the Catuvellauni, the most powerful tribe in south eastern England prior to the Roman Conquest. The Wheathampstead settlement is considered to have been a possible precursor to Verlamion and later a satellite of the main centre, perhaps serving as a place of refuge and defence, although defence may have become less important as the Catuvellauni extended and consolidated their territory in the early first century AD. Beech Bottom Dyke, possibly in association with other less durable markers, is thought to have defined the boundary of a substantial estate, perhaps that which supported the domestic economy of the tribal centre or its most prominent inhabitants. Given its impressive dimensions, the Dyke must have served as a considerable symbol of authority, and it will provide significant insights into the nature of the society by whom it was constructed. The lower profile of the ditch remains buried by accumulated silts and together with the banks will retain valuable evidence relating to the manner and date of the Dyke's construction. Soils sealed beneath the banks will contain evidence illustrating the appearance of the surrounding landscape prior to the construction of the Dyke, and the basal silts in the ditch may provide environmental evidence for changes effecting this landscape alongside the development of the Roman town of Verulamium.


The monument includes a substantial late Iron Age boundary ditch, or dyke, situated on the eastern outskirts of St Albans, extending some 1.4km to the north east and 250m to the west of the junction of Beech Road and Harpenden Road and lies within three areas of protection.

To the east of the road junction the Dyke ascends a slight valley for about 700m towards the point where its alignment is crossed by Valley Road. The ditch here measures 30m-35m in width and up to 10m in depth, with steep sides descending to a narrow flattened area of accumulated soil across the base. Sections of the banks which originally flanked either side of the ditch can still be seen along the northern edge of the ditch to the rear of the properties on Old Harpenden Road and extending some 150m westwards from Valley Road along the southern side of the Dyke. This latter section of bank may have widened at a later date to form a cart track leading to a small quarry alongside the southern scarp of the ditch. A narrow causeway, thought to have been formed from quarry upcast, crosses the Dyke at this point.

Valley Road crosses the Dyke on a raised causeway which has effectively sealed the ditch and earlier deposits in the base. This buried section is included in the scheduling. The section of the Dyke between Valley Road and the railway line (300m to the north east) is particularly well preserved. This section of the ditch measures 20m-25m in width, 5m in depth and is flanked by largely uninterrupted banks on both sides. The southern bank averages 5m in width and 1.5m in height, slightly larger than the northern bank which retains remnants of a post-medieval hornbeam hedgerow. The ditch and the northern bank remain visible for a further 80m to the east of the railway embankment, and the infilled line of the ditch (a slight depression defined by upstanding sections of the bank) continues eastwards towards the driveway to The Glen. To the east of the driveway, in the grounds of No 144 and Nos 142-142e St Albans Road, the ditch reappears as a substantial depression flanked by the northern bank.

Further east the ditch runs within the rear property boundaries of Nos 138 to 128 St Albans Road and is largely infilled. The extent of the buried feature is known from earlier maps, and it can still be detected as a very slight depression in the garden of No 130.

Archaeological observations of sewer trenches dug in 1932 demonstrated that the Dyke continued some 400m south west beyond the Beech Road-Harpenden Road junction. On the evidence of a hoard of Roman coins found some 3m above the base of the ditch, this section appears to have become partly infilled by the 2nd century AD. The northern edge of the ditch is still visible, measuring up to 1.8m in height and extending westwards for about 250m along the southern verge of Batchwood Drive. A substantial part of the infilled ditch remains largely undisturbed between the carriage way and the properties to the south of Batchwood Drive and is included in the scheduling.

The Dyke is thought to have been constructed in the late pre-Roman Iron Age, the period from the mid 1st century BC to the Roman invasion of AD 43. It lies between two well known Iron Age settlements: Verlamion (the name given to pre-Roman Verulamium known from coins minted on the site in the Late Iron Age), across the valley of the River Ver to the west, and Wheathampstead on the River Lea some 4km to the north east. Both settlements were also partly enclosed by earthworks: Devil's Dyke and Wheeler's Ditch around Verlamion, and The Moat, The Slad and a separate Devil's Dyke surrounding Wheathampstead. It has been suggested that the Beech Bottom Dyke formed a link between the two settlements and formed part of a territorial boundary isolating the high ground to the south between the Rivers Ver and Lea. The Dyke terminates some 3.5km short of Wheathampstead, however the St Albans-Sandridge Road continues on the same alignment and may prove to perpetuate the line of a less substantial variant of the boundary.

In addition to the Valley Road causeway the following items are excluded from the scheduling; all fences and walls, the surfaces of all modern roads, paths, yards and driveways; all lamp posts and drain covers and all workshop and garden buildings. The ground beneath all these items is, however, 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
Saunders, C, Havercroft, A B, 'Hertfordshire Archaeological Journal' in Excavations on the Line of the Wheathampstead By-pass 1974-77, , Vol. 8, (1982), 31-39
Wheeler, R E M, Wheeler, T V, 'Society of Antiquaries of London Research Report' in Verulamium: A Belgic and Two Roman Cities, , Vol. XI, (1936)
Title: Herts XXXIV NE Source Date: 1925 Author: Publisher: Surveyor: 6 inch edition


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

Your Contributions

Do you know more about this entry?

The following information has been contributed by users volunteering for our Enriching The List project. For small corrections to the List Entry please see our Minor Amendments procedure.

The information and images below are the opinion of the contributor, are not part of the official entry and do not represent the official position of Historic England. We have not checked that the contributions below are factually accurate. Please see our terms and conditions. If you wish to report an issue with a contribution or have a question please email [email protected].