Scheduled MonumentsWalesPlas Baglan
Medieval · Castle

Plas Baglan

Wales
Cadw SAM GM358
Period
Medieval
Site type
Castle
Broad class
Defence
Nation
Wales
Boundary

Scheduled area

© Mapbox · © OpenStreetMap contributors · Boundary data © Cadw

Overview

History & significance

Plas Baglan is a medieval castle situated in Wales and protected by Cadw under reference GM358. The site occupies ground underlain by the Pennine Lower Coal Measures Formation and South Wales Lower Coal Measures Formation, a Westphalian-age sequence of mudstone, siltstone, sandstone, coal, ironstone and ferricrete that shaped the local landscape. This geological foundation, characteristic of the South Wales coalfield region, would have influenced both the castle's construction and the resources available to its medieval occupants.

The castle represents the medieval period's fortified domestic architecture in Wales, when such structures served defensive, administrative and residential functions for their lords. The choice of location on this coal-bearing bedrock reflects the strategic or territorial considerations of its builders, situated within a landscape rich in mineral deposits that would later drive industrial development in the region.

Today Plas Baglan remains an important element of Wales's medieval heritage, protected recognition reflecting its archaeological and historical significance. The monument contributes to understanding of medieval Welsh settlement patterns and the use of naturally defensible or strategically important sites during the period when such castles dominated the Welsh landscape.

Plas Baglan is a scheduled monument protected by Cadw under reference GM358. View the official record →

About this monument

Questions & answers

What is Plas Baglan?

Plas Baglan is a medieval castle situated in Wales and protected by Cadw under reference GM358.

What period does Plas Baglan date from?

Plas Baglan dates from the medieval period, and is classified as a castle. It is one of over 32,000 scheduled monuments protected across the UK.

Who is responsible for protecting Plas Baglan?

Plas Baglan is a Scheduled Ancient Monument, legally protected by Cadw — the body responsible for designating and safeguarding heritage sites in Wales. The official designation reference is GM358.

What other scheduled monuments are near Plas Baglan?

Several scheduled monuments lie within 10 km, including Ergyd Isaf Round Barrows (5.3 km), Chain Home Low Radar Station, Margam (6.5 km), Wrecking site of the Ann Francis (6.8 km).

Unlimited access

Everything a full report reveals about Plas Baglan

This page is just one thread. A full Aubrey report pulls together 13 strands of Plas Baglan's history, each drawn from the record and mapped to the exact spot:

Overview
An interactive map of the location with every monument and battle plotted, and a plain-language history built only from what the record holds.
Monuments
The legally protected scheduled monuments around the location, each with its period, type and significance.
Battlefields
The battles and sieges fought on this ground, mapped and set on a timeline of the wider conflict.
Roman Britain
The Roman roads, forts and towns near here, and the Iron Age people who held the land before Rome arrived.
Civil War
The Civil War fighting, garrisons and recorded militaria in this area, woven into the arc of 1642 to 1651.
Geology
The bedrock beneath the site, its age and rock type, reaching back hundreds of millions of years.
Local Names
What the street and field names around here actually mean, and the history buried inside them.
Historical Maps
Ordnance Survey maps from the 1800s, layered over the location as it stands today.
Literature
The books, county histories, charters and archives that mention this place, quoted with their sources.
Legal
The protected sites nearby and the metal-detecting, access and treasure laws that apply to this ground.
Spotlight
A deep dive into the most remarkable, lesser-known history of the place, traced back to the record.
Target Zones
For detectorists: the most promising ground to search nearby, ranked by confidence, with what to expect.
Timeline
The whole story of the location told era by era, from prehistory to the present day.
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Every location is different. Not every section appears for every place, only what the historical record actually holds turns up in a report.

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The ground beneath

The bedrock under Plas Baglan

Plas Baglan stands on Pennine Lower Coal Measures Formation And South Wales Lower Coal Measures Formation (Undifferentiated), bedrock that formed in the Westphalian. The rock here is mudstone, siltstone, sandstone, coal, ironstone and ferricrete.

The wider landscape

Around Plas Baglan

Caerphilly CastleArchaeological site · ~25 miles