Mynydd Hendre-ddu or Mynydd Hendreddu is a

mountain A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher t ...

in southern

Snowdonia Snowdonia, or Eryri (), is a mountainous region and National parks of the United Kingdom, national park in North Wales. It contains all 15 mountains in Wales Welsh 3000s, over 3000 feet high, including the country's highest, Snowdon (), which i ...

, Wales. It is one of a line of mountains running from

Mynydd Dolgoed Mynydd Dolgoed or Craig Portas is a mountain in southern Snowdonia, Wales. It is a long ridge running from a low summit between the valleys of the Afon Angell and the Nant Ceiswyn, north east to the cliff of Craig Portas above Dinas Mawddwy. The ...

in the north, through

Mynydd Llwydiarth Mynydd Llwydiarth is a mountain in southern Snowdonia Snowdonia, or Eryri (), is a mountainous region and National parks of the United Kingdom, national park in North Wales. It contains all 15 mountains in Wales Welsh 3000s, over 3000 feet hi ...

to Mynydd Hendre-ddu and on to Mynydd y Foel, Y Grug, Mynydd Tri-Arglwyd and Mynydd Gwyn to the south of the village of

Aberangell Aberangell () is a village in Gwynedd, Wales. Geography Aberangell stands at the confluence of the Afon Angell and the Afon Dyfi, and lies within Dinas Mawddwy community. On the north side of the village, the long ridge of Pen y Clipau runs d ...

. It forms the watershed between Nant Llwydiarth, which flows to the south-west and into the

Afon Dulas The Afon Dulas, or North Dulas, is a river forming the border between Merionethshire/Gwynedd and Montgomeryshire/Powys in Wales. Another river called Afon Dulas joins the Dyfi from the south, upstream of its confluence with the North Dulas: loca ...

, and streams flowing into

Afon Angell The Afon Angell is a river in Gwynedd, Mid Wales. The river flows eastwards from its source on the eastern flank of Mynydd Dolgoed, joining the Afon Dyfi at the small village of Aberangell. The river was known for its salmon and trout fishing ...

to the north, which flow east into the

River Dyfi The River Dyfi (; ), also known as the River Dovey ( ), is an approximately long river in Wales. Its large estuary forms the boundary between the counties of Gwynedd and Ceredigion, and its lower reaches have historically been considered the b ...

. The summit is notable for a set of parallel ridges about across and long that run across it. On the northern slope of the mountain lay the

Hendreddu quarry Hendreddu quarry was a slate quarry about three miles west of Aberangell in Merioneth (now Gwynedd), North Wales, near Nant Hendreddu on the slopes of Mynydd Hendre-ddu. The quarry worked the Narrow Vein, the highest-quality slate vein in the ...

which was connected to Aberangell by the

Hendre-Ddu Tramway The Hendre-Ddu Tramway was a narrow-gauge industrial railway built in 1874 in Mid-Wales to connect the Hendre-Ddu slate quarry to Aberangell station on the Mawddwy Railway. It consisted of a main line long and several branch lines and s ...

. Mynydd Hendre-ddu is one of the Dyfi hills.

References

{{coord, 52.69279861, N, 3.77413743, W, region:GB_type:mountain, display=title Mountains and hills of Snowdonia Landmarks in Wales Mountains and hills of Gwynedd Mawddwy Dyfi Hills