A small part of the community of Llanddew to the south of the village lies within Fforest Fawr Geopark.

The lie of the land

The community ranges in height from about 155m beside the Afon Honddu north of Brecon to over 320m below Yr Allt in the east.

Solid rock

The underlying rocks are sandstones and mudstones which were laid down during the Devonian Period.  These rocks can be seen in the sides of the Honddu gorge.

The low hills which characterize the area are formed from sandstones of the St Maughan’s Formation and mudstones of the Raglan Formation.

A major fault – the Cribarth Fault - runs SW to NE through the village of Llanddew.

Legacies of the Ice Ages

Surrounding hillsides are plastered with glacial till and relate to the presence of the major Usk Valley Glacier during the ice ages.

It is thought that the River Usk formerly flowed to the north of Brecon around the back of both Pen-y-crug and Slwch Tump in the vicinity of Llanddew village.  Glacial action diverted it onto its present more southerly course.

Archaeology

There are remains of a castle at Llanddew and of a motte and bailey at Alexanderstone.

Maps

Geology

Sheet 213 ‘Brecon’ of the British Geological Survey’s 1:50,000 map series of England and Wales gives full coverage of both the bedrock geology and superficial deposits of the Community area.  BGS publishes a 'sheet explanation' to accompany the map.

General

The following Ordnance Survey maps cover the Community:

• Landranger sheet 160 'Brecon Beacons' (1:50,000 scale)
• Explorer sheet OL12 'Brecon Beacons National Park/Western area' (1:25,000 scale)

Public transport

Bus services serve the nearby town of Brecon. The nearest railway stations are at Builth Wells, Llandovery, Abergavenny and Merthyr Tydfil to the north, west, east and south respectively.

See Traveline Cymru for bus and train services including stops, timetables and route-planning information.