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A40/Brecon - Carmarthen

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< A40
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From:  Brecon (SO031283)
To:  Carmarthen (SN411191)
Via:  Llandovery
Meets:  A470, B4601, A4067, A4069, A483, A482, B4302, B4297, B4310, A485, A484, B4300, A48, A484
Former Number(s):  A481, A482, A4080
Old route now:  A4069, A484, B4312
Highway Authorities

North and Mid Wales Trunk Road Agent • South Wales Trunk Road Agent


Brecknockshire • Carmarthenshire

Route outline (key)
Arrowwest.jpg West Carmarthen - Haverfordwest
A40 Brecon - Carmarthen
East Arroweast.jpg Abergavenny - Brecon

At a roundabout at the western end of the Brecon bypass we say farewell to the A470, which passes through the heart of the Beacons on its way to the Valleys communities and to Cardiff beyond. The A40 continues its relentless push westward, once again following the Usk Valley. The road is very rural in character, with tight bends, lots of peaks, and dips in the road making overtaking difficult, if not impossible. Unlike the valleys of the South Wales coalfields to the south (which are littered with ribbon towns), this area is green – the fields are filled with sheep – the ground is too steep to do much else. Standing at a lay-by on this stretch, it is difficult to imagine that this is the same A40 that six lanes of traffic thunder along at Greenford in West London.

At Sennybridge there was an unusual feature for a largely unimproved rural road: a partially grade-separated junction served the A4067, which leads via Cwm Treweryn up past Crai Reservoir to the watershed between the Usk and Swansea Valleys and ultimately to Swansea itself. The Neath to Brecon railway crossed over the A40 at this location until its closure in 1962. Following this event, the section of the A4067 between the village of Defynnog and the A40 junction was relaid along a short stretch of the closed line, to take through traffic away from the centre of Sennybridge, and the old railway bridge was used as a GSJ for eastbound traffic heading towards Brecon. This arrangement remained in place until the late 1990s, when the bridge stood in need of prohibitively expensive repairs in order to to remain usable, and the decision was therefore taken to dismantle it and convert the meeting of the A4067 and A40 into a normal flat junction for all traffic.

We continue west through a much narrower valley to Llandovery, where we meet another north-south artery: the A483. Beyond the town, we follow the Towy valley, picking up the A482 at Llanwrda then through to Llandeilo. Having passed through the narrow confines of the Brecon Beacons, the road now enjoys a much broader outlook. The Towy Valley is wide and relatively flat along the bottom, allowing more freedom in choice of route for the people who first walked through this valley.

To the north east of Llandeilo a roundabout marks the point where the A483 leaves our route, passing through the town itself, then heading south to the end of the M4 at Pont Abraham. On the other hand, the A40 passes to the north of Llandeilo, passing the north side of the national Trust owned Dinefwr Park estate before continuing to Carmarthen.

The road network in Carmarthen is now unrecognisable from twenty years ago. Carmarthen was once a bottleneck as all traffic competed to pass round a gyratory near the railway station. For many years there was a lifting bridge on the west bound side of the gyratory, but that is no longer there. These days, a series of bypasses take the A40 to the south of the town, where the A40 meets the A48 again, a dual carriageway running as an extension of the M4.

Abbey Way Gyratory • Abergwili Roundabout • Arle Court Roundabout • Asthall Barrow Roundabout • Bank • Benhall Roundabout • Blackbridge Roundabout • Bridgend Square • Brynich roundabout • Burford Roundabout • Canaston Bridge Roundabout • Coxs Meadow • Cutteslowe Roundabout • Denham Roundabout • Ealing Common • Eden Roundabout • Elmbridge Court Roundabout • Eynsham Roundabout • Forest Gate Junction • Gipsy Corner • Golden Valley Junction • Greenford Roundabout • Hanger Lane Gyratory • Hardwick Gyratory • Headington Roundabout • Highnam Corner • Highnam Roundabout • Hildersley Roundabout • Hillingdon Circus • Holborn Circus • Holland Park Roundabout • Holtspur Temporary Terminal • Holtspur Roundabout • Knaves Beech Interchange • Lancaster Gate Gyratory • Llanboidy Road Roundabout • Llandeilo Roundabout • London End Roundabout • Marble Arch • Marston Interchange • Marylebone Flyover • Old Beaconsfield Roundabout • Over Ross Roundabout • Over Roundabout • Oxford Circus • Paddington Interchange • Pedestal Roundabout • Penblewin roundabout • Pensarn Roundabout • Perivale • Polish War Memorial • Pont Lesneven roundabout • Prendergast Roundabout • Pyebush Roundabout • Rafael roundabout • Raglan Interchange • Raglan Roundabout • Robeston Wathen Roundabout • Salutation Square • Savoy Circus • Scotchwell roundabout • Shepherds Bush Green • Square and Compass • St Giles Circus • St Pauls Gyratory • St Clears Roundabout • Stokenchurch Interchange • Sturt Farm Interchange • Swakeleys Roundabout • Tarell roundabout • Target Roundabout • Three Pigeons • Travellers Rest (Carmarthen) • Weston Cross • Westway Roundabout • Wheatley Interchange • Wilton Roundabout (Ross) • Windyhall roundabout • Withybush roundabout • Wolvercote Roundabout • Wood Lane
Related Pictures
View gallery (330)
A40 Camarthan - Coppermine - 6909.jpgA40 dual carriageway near Glewstone - Geograph - 1576474.jpgSnow on the A40 at Swinbrook - Geograph - 349319.jpg1960s Cheltenham Town Centre Proposals.pngThe A40 and Little Doward from the Whitchurch road bridge - Geograph - 780451.jpg
Other nearby roads
A40 • A438 • A470 • A4059 • A4062 (Brecon) • B4520 • B4557 (Brecon) • B4558 • B4559 • B4601 • B4602 • Ffordd Cambria • NCN8 • T75 (Britain) • T77 (Britain)
A40 • A474 • A476 • A483 • B4300 • B4302 • T18 (Britain) • T79 (Britain)

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