Machynlleth

Machynlleth is a town in the Dyfi Valley in mid Wales. Situated in the west of Montgomeryshire, it lies close to the borders with Cardiganshire and Merionethshire.

Machynlleth in 1923. The road network is basically the same today.

Because of the imposing geography of nearby mountains, including Cadair Idris, and the Dyfi estuary, there is little space to practically put a road on, and consequently the road network today is more or less unchanged since classification.

The town is a significant bottleneck on the Welsh road network since the A489 meets the A487 in the town. There was previously a problem with the only crossing of the River Dyfi being the 19th Century Dovey Bridge. Because the bridge is a Grade II listed structure, it could not simply be widened and replaced, and required regular repair due to HGVs striking the bridge. Strikes and also flooding resulted in the bridge being closed, requiring all traffic to take a 20 mile detour, including one notorious incident in 2010 where it was closed for several weeks. A further problem is a bridge under the local railway next to the station, which regularly floods.

Transport Wales built New Dyfi Bridge as a bypass bridge, slightly upstream of the existing one. It opened on 2 February 2024. Additional flood mitigation measures were also being put in place.

Routes

Route	To	Notes
A487	Aberystwyth
A487	Dolgellau (A470)
A489	Y Drenewydd / Newtown, Y Trallwng / Welshpool (A470)
A493	Aberdyfi, Tywyn
B4404	Llanwrin