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and the Beacons


This is the Tâf Fawr Valley in the Parish of Vaynor, which was in Breconshire until 1974.  At one time this valley was mainly rough grazing pasture for sheep; although there were also a number of lime kilns situated here. This was an agricultural area until the Cardiff Waterworks Company was given permission in 1884 to impound water here. The Cantref Reservoir here dates from 1892 and caused the farms of Glancrew, Crewisaf, Abercrew and Blaentaf to be demolished.  The construction of the Llwyn-On Reservoir, which opened in 1926, made a huge difference to the landscape here. In this valley were the hamlets of Ynysyfelin and Nantddu.

The hamlet Ynysyfelin was located on the right bank of the river, near the bridge over the Taf Fawr. Before the area was flooded in 1914 there were farms, small holdings,  the Red Lion and the Farmers’ Arms, the Pwllcoch woollen mill a school and a chapel here. Bethel Baptist Chapel, founded in 1799 by members of Zion Twynyrodyn, still survives today because it was rebuilt elsewhere. It reopened in July 1914 at  Llwynon, a small hamlet straddling either side of the A 470 about 2 miles from Cefn Coed.  The farm, which once stood opposite Bethel chapel, Troedyrhiw Farm, is now under the reservoir.

The hamlet of Nantddu was north of Ynysyfelin and at the confluence of the Nantddu brook and the Taf Fawr river. Here was St Mary’s church, with its vicarage, and a number of pubs, including the Tredegar Arms. A good deal of the land was owned by Lord Tredegar, who had a hunting and shooting lodge here ( now the greatly extended Nantddu Hotel ). Land here was purchased by the Cardiff Corporation and well outside the jurisdiction of Merthyr Tydfil County Borough Council.  During the period of reservoir building hundreds of ‘navies’ came to Cwm Tâf  and a ‘navies’ line ran from Cefn Coed to Cwm Tâf. Men and limestone were carried from the quarry under the Ffrwd farm to Cwm Tâf. These workers lived in overcrowded conditions in ‘huts’, until the reservoir was completed and then they moved on to the next job.

In 1946 the Forestry Commission purchased 2,342  acres of land in the upper Taf Fawr. The Garwnant Centre is the centre for the Coed Tâf Fawr woodlands. There is a visitors centre, exhibition, gift shop and a café. There are woodland walking trails, a family cycle route and a toddlers play area. The village of Llwyn- On consists of houses, which were originally council houses, a guest house and houses built by the Forestry Commission; together with the old Llwyn-On farmhouse and the new Capel Bethel Baptist Chapel.  Little has been written in detail about the history of this area.

The farms and farmers are all listed in the 1840s tithe schedules and exploring the area reveals interesting small bridges and pathways. Unfortunately the A470 has become increasing busy in the last decade as it is the main route between Mid and North Wales and Cardiff.


<click on the photo to enlarge>


Cwmtaff (Llwyn Onn) Reservoir

(Photograph Courtesy of Chris Matthews)

Llwyn Onn Reservoir.

  BreconBeaconsLLwynOnnRes.JPG (123983 bytes)

Click Here

To See the Building

Of The






Pont yr Daf. (Bridge over the Taff).

Now under Llwyn On reservoir.

Pont Yr Daf.

Only visible when Llwyn Onn is in drought.

Cwmtaff__Llwyn-On_Bridge_VisibleAtDrought.JPG (147764 bytes)


Pont y daf Bridge taken during a drought.

(Courtesy of Robert Thomas, of West Grove.)


More Photos of Pont Y Daf Bridge in the Drought of 1982

(Photograph courtesy of Wendy Rees & Gareth Rees)


Saint Mary's Church, Nantddu.





Llwyn Onn, Pont y Newydd ar Daf bridge.

Jack Morse, at the "Tin Huts".

Photograph Courtesy of Bill "Engine" Jones.

(Additional Information Courtesy of Bernard Morse)

Cwmtaff_RegMorse_TinHuts.JPG (204955 bytes)

Cwnfelin Baptist Chapel, now under Llwyn On Reservoir.

Capel Bethal Cwmtaff

Cwmtaff before the reservoir.


"The Valley that died"

From the Merthyr Express


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