Waun-Ddu

Mynydd Bach Trecastell is a hill on the border between the counties of Carmarthenshire and Powys in southwest Wales. It lies within the Black Mountain range of the Brecon Beacons National Park and Fforest Fawr Geopark. Its summit is plateau-like and reaches a height of 412m at OS grid ref SN 827312 at Y Pigwn. The name signifies the 'little hill of castle town'.

The Usk Reservoir (Welsh: Cronfa Wysg) is located in the upper Usk Valley, at 1,006 feet (307 m) above sea level, in the western part of the Brecon Beacons National Park, Wales. The county boundary between Carmarthenshire and Powys runs through the reservoir which lies about six miles to the north of the Black Mountain escarpment. It is an important landmark for walkers on the mountain range.

Mynydd Myddfai is a hill 4.5 miles southeast of Llandovery in the county of Carmarthenshire, southwest Wales. It lies within the Brecon Beacons National Park and Fforest Fawr Geopark. The hill is in the form of a broad ridge aligned southwest to northeast with three or four distinct tops separated by cols. The northwest side drops steeply away towards the village of Myddfai whilst the other side is a more shallow slope down towards Glasfynydd Forest which encircles Usk Reservoir. The plateau surface of the hill rises to a height of 440m at OS grid ref SN 806297 where a trig point has been erected.

Babel is a hamlet in Carmarthenshire, Wales.

Cwmwysg (Welsh for "Usk valley") is a small rural village southwest of Trecastle in the valley of the Usk river, Powys, Wales. It includes the Saron Independent Chapel, originally built in 1822 and rebuilt in 1856. The humpback stone river bridge over the Usk is Grade II listed. The Welsh painter Aneurin Jones (1930–2017) was born in Cwmwysg.

The Cefn-cerig road, a road near Cefn-cerig Farm, Llandovery, Wales, is the location of the Global Boundary Stratotype Section and Point (GSSP) which marks the boundary between the Aeronian and Telychian stages of the Silurian period on the geologic time scale. The GSSP was ratified in 1984. The boundary is defined as a point immediately above the highest record of the brachiopod Eocoelia intermedia and below the first appearance of the succeeding species Eocoelia curtisi. The boundary also corresponds to the incoming of the acritarchs Deunffia monospinosa, Domasia bispinosa and Pterospermella. The section, part of the Wormwood Formation, is sandstone and siltstone.

St Michael's Church is the Anglican parish church for the parish of Myddfai, south of Llandovery, in Carmarthenshire, Wales. The present building dates from the 14th and 15th centuries with restoration work being undertaken in 1874, when a bellcote was added, and again in 1926. The church has a double nave and twin parallel roofs. The south nave may be the oldest part of the church and dates to the fifteenth century. The interior of the church has original plaster-panelled roofs with moulded timber ribs throughout the building. The church was designated as Grade I-listed building on 7 August 1966, as a fine example of "a largely complete medieval church of a scale and detail unexpected in so rural a location. Unusually intact interior including arcades, complete surviving late medieval roofs and the extensive survival of late medieval window tracery. The double nave form is relatively rare in the county, being more common in Powys".

Myddfai () is a small village and community in Carmarthenshire, Wales. It is situated south of Llandovery in the Brecon Beacons, and has a population of 415, decreasing to 398 at the 2011 census. The village is a popular tourist destination on the western edge of the Brecon Beacons, famous for the history and heritage of the Physicians of Myddfai and the legend of ‘The Lady of The Lake’ and provides a central location to visit a wide range of interesting places, such as gardens, castles and The Heart of Wales Railway. The community is bordered by the communities of: Llanddeusant; Llangadog; Llansadwrn; Llanwrda; Llandovery; and Llanfair-ar-y-bryn, all being in Carmarthenshire; and by Llywel in Powys.

Abercrychan is a small village in the north-east of Carmarthenshire. It is located on the A483, 4 miles to the north of the town of Llandovery. The village is named after the River Crychan, a small stream that flows into the River Brân, near the village. Crychan Forest is on the slopes to the east of Abercrychan.

Llwynywermod (Welsh: Llwynywermwd; Welsh pronunciation: [ɬʊi̯n.ə.wɛr.mʊd]), also known as Llwynywormwood, is an estate owned by the Duchy of Cornwall, just outside the Brecon Beacons National Park in Carmarthenshire, Wales. The 192-acre (0.78 km2) estate is near the village of Myddfai, Llandovery, Carmarthenshire. The nearest station is Llandovery, which is 2 miles (3.2km) from the estate.

The Afon Gwydderig is a tributary of the Afon Brân. It rises as the Nant Gwydderig on the southern slopes of Mynydd Bwlch-y-groes, about 3 miles (4.8 km) North of the small village of Llywel, Powys. The A40 runs next to the river from Llywel as far as Llandovery, Carmarthenshire. The Gwydderig crosses the boundary between Powys and Carmarthenshire at the village of Halfway. It joins the Brân in Llandovery, Carmarthenshire, about 1+1⁄2 miles (2.4 km) upstream of the confluence of the Brân with the River Towy. The Gwydderig therefore forms part of the Towy's catchment basin and drains into the Bristol Channel at the Towy estuary.

Crychan Forest Tracks is a Site of Special Scientific Interest in Carmarthen & Dinefwr, Wales. It was chosen as a special stage in the British Rally from 2006 to 2008.