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Caernarfon Castle - Geograph - 822633.jpg
Caernarfon Castle
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Bangor • Porthmadog
Places related to the A487

Caernarfon in north west Wales is the county town of Caernarfonshire and the seat of Gwynedd Council. A port and tourist centre, it is a Primary Destination on the A487. The town is perhaps best known for being home to the largest of the medieval castles in Wales, which has numerous spiral staircases, towers, galleries and wall walks to explore. Less well known are the old town walls which stand slightly to the north of the castle and still form a more or less complete circuit. The town centre sits partly inside and partly outside the walls, with several arches permitting traffic to pass between.

Old maps refer to the archaic Anglicised names of Carnarvon (1923 MOT) or Caernarvon (early One Inch Seventh Series).

Roads History

Caernarfon lies at the north eastern corner of Wales coastal trunk route, the A487. Until the bypass was completed in 2022, the trunk route passed through the town, originally following Bangor Street and Pool Street, now the B4419. As traffic volumes grew, congestion became a recurrent problem, leading to the construction of the Inner Relief Road, which was opened as the A487 on 2 February 1981. The contractor was Robert McGregor & Sons with costs at more than £4 million. This relief road included a small GSJ, Eagles Junction, with a two lane flyover for through traffic, and a new roundabout at the northern end, while existing streets were turned into a small gyratory at the southern end. In 1994 a new bridge was built across the Afon Seiont at the southern end of the town, bypassing the dogleg across the old Pont Seiont, and in 1998 an old, disused railway tunnel was repurposed for road traffic to help further ease congestion in the town.

Further out from the town centre, a series of unclassified roads former an informal bypass, connecting to the A487 at either end, and meeting the A4086 and A4085 along the way. This route included an awkward dogleg across the Afon Seiont on the A4086, but otherwise proved busy enough for the small village of Caeathro to be bypassed with a new roundabout for the A4085. All of this tinkering only really prolonged the inevitable, and the new bypass was finally opened in 2022, giving proper relief to Caernarfon.


The four A roads which converge on Caernarfon still carry similar numbers to those allocated in 1922. However, until they swapped routes in the 1960s, the A487 took the mountain route via Beddgelert while the A4085 took the coastal route, and was indeed the trunk route. This meant that originally it was the A499 that did the final couple of miles from Dinas into Caernarfon. The Caernarfon Bypass, incidentally, includes a bypass of Bontnewydd to the south, and the old alignment has been rather lazily renumbered as the A4871, rather than extending the A499 back into town, or perhaps the A4087 which follows part of the bypassed route between Caernarfon and Bangor to the north east. The short B4419 within the town is actually part of a longer route which, until the ferry service closed in the 1950s, connected across the Menai Strait to Anglesey where a much longer section of B4419 survives. The only other classified route in the town is the B4366, which comes in from the north east and terminates at a roundabout on the A4086.


Route To Notes




Porthmadog former A4085






Llanberis Also signed to Snowdon Mountain Railway


Bangor Former A487


Porthmadog former A499 / A487




various streets in town centre

Related Pictures
View gallery (16)
The flyover from the northern footbridge - Geograph - 357046.jpgTanrallt aka Stryd Mari - Geograph - 351370.jpgView northwards along Bangor Street, Caernarfon - Geograph - 1591322.jpgThe A487(T) as it enters Caernarfon.jpgA4871-pont-seiont3.jpg
Places in Wales
Major destinationsBridgend Pen-y-bont ar Ogwr • Cardiff Caerdydd • Cwmbrân • Llanelli • Merthyr Tydfil Merthyr Tudful • Neath Castell-nedd • Newport Casnewydd • Port Talbot • Swansea Abertawe • Wrexham Wrecsam
Other primary destinationsAbergavenny Y Fenni • Aberystwyth • Bala Y Bala • Bangor • Betws-y-Coed • Brecon Aberhonddu • Builth Wells Llanfair-ym-Muallt • Caernarfon • Cardigan Aberteifi • Carmarthen Caerfyrddin • Chepstow Cas-gwent • Conwy • Dolgellau • Fishguard Abergwaun • Haverfordwest Hwlffordd • Holyhead Caergybi • Llandeilo • Llandovery Llanymddyfri • Llandrindod Wells Llandrindod • Llandudno • Llangollen • Llangurig • Machynlleth • Milford Haven Aberdaugleddau • Mold Yr Wyddgrug • Monmouth Trefynwy • Newtown Y Drenewydd • Pembroke Dock Doc Penfro • Porthmadog • Queensferry • Rhayader Rhaeadr Gwy • Ruthin Rhuthun • St Clears Sanclêr • Tenby Dinbych-y-pysgod • Welshpool Y Trallwng
Other placesAberaeron • Abergele • Barry Y Barri • Beaumaris • Caerphilly Caerffili • Cardiff-Wales Airport Maes Awyr Caerdydd-Cymru • Denbigh Dinbych • Ebbw Vale Glen Ebwy • Flint Y Fflint • Harlech • Hirwaun • Lampeter Llanbedr Pont Steffan • Llangefni • Pontypool Pont-y-pŵl • Pontypridd • Prestatyn • Presteigne Llanandras • Pwllheli • Rhyl Y Rhyl • St Asaph Llanelwy • St Davids Tyddewi • Treherbert • Treorchy Treorci • Y Felinheli

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