Offa's Dyke can be seen in several places in the Forest.
It is first recognisable just in the western end of the Lydbrook Viaduct.
From here it shows at intervals until the road to Bicknor cuts through its path, and here it is evident, both on the bank and towards the top of the hill opposite,
whence a combination of dyke and cliff marked the edge of Mercia as far as Symond's Yat,
where it seems to merge with the vallum
of the Rock Promontory Fort.
From this point no trace of it can be seen for ten miles since the cliffs are so high,
but just below Redbrook it becomes visible again,
and can be followed fairly easily until it comes to an end in a bunch of scrub in a field at Tutshill,
near to the old look-out tower which was later erected as an outpost of Chepstow Castle.
A continuation of the Dyke runs across the Beachley Peninsula to reach the Severn at Sedbury,
and may be traced on portions of the higher ground.
Here it bears traces of being used for later defence works,
but at certain spots it retains a nearly perfect form.
(Roman British archaeol.
a rampart; a wall of sods, earth, or other material, esp
. of that thrown up from a ditch.
The text above is from:
by R.J. Mansfield
publisher: the author 1964