|Location Map ( geo)
|19.7 miles (31.7 km)
|A487, B4410, A498, B4418
|Route outline (key)
Penrhyndeudraeth - Beddgelert
The route starts at a crossroads on the A487 at Penrhyndeudraeth, where the road opposite cuts across the estuary on Pont Briwet, providing a shortcut to the A496. It runs northwards along the High Street at first, passing a scattering of shops before becoming more suburban as it starts to climb. Curving round to the north east, Fron Heulog becomes very narrow, barely wide enough for two cars to pass, and even the wider bits can be blocked by parked cars. The road is climbing across a steep hillside, and in places traffic is looking out across the rooftops below, while the houses above stand up another terrace above. The Ffestiniog Railways Penrhyn station is passed and then the road winds alongside the narrow gauge railway as far as a gated level crossing, just before which the white centre line resumes. Soon after, the road sweeps around a left turn to avoid a rocky outcrop, and leaves the town behind, plunging into woodland.
Despite the steepness of the hillside, the road has only climbed to around 50m, and this is soon lost as it descends through the trees onto the Traeth Mawr, the vast flat valley floor of the Afon Glaslyn. The road heads out across the plains, with a long straight cutting across fields to the small village of Garreg where the B4410 is crossed at a staggered crossroads. The road now sticks close to the base of the hills as it continues to work its way north. A few sharp corners and narrowings of the road are encountered, but in between are long stretches which appear to have been widened and straightened a little at some point in the past. A very sharp left bend at Tan-lan briefly sees the road cross the flats, before another sharp left over a bridge returns it to the foothills. At length, the road turns away from the Traeth Mawr, following the Afon Dylif upstream for a while, before crossing it and then climbing over a slight rise to also cross the Nanmor.
Although enclosed by low hills, the route now crosses another area of low lying land on a long straight, with rough fields and patches of woodland to either side. Another slight climb with some tight bends takes it to a bridge under the Welsh Highland Railway, the two winding side by side into the tiny village of Nantmor. Here the route reaches the mouth of the Aberglaslyn Pass, crossing the Afon Glaslyn on Pont Aberglaslyn, and finding a T-junction with the A498 on the western bank. There is then a multiplex with the A498 as it winds north through the Aberglaslyn Pass into the beautifully picturesque village of Beddgelert. The road winds between the old stone houses to cross the Afon Colwyn on Beddgelert Bridge, with a T junction on the north bank where the A498 TOTSOs right, and the A4085 regains its number by turning left.
Beddgelert - Caernarfon
Beddgelert lies in a bowl between the hills at the confluence of the Colwyn and Glaslyn, with the vast bulk of Snowdon rising to the north. As such it is a mecca for hillwalkers, and can be very busy in the summer months. The road now follows the Afon Colwyn along the south edge of Snowdon, climbing steadily through the narrow valley as it continues to shadow the Welsh Highland Railway, which runs through the trees on the far side of the valley. As the road climbs, it crosses steep fields which tumble down the mountain and passes occasional houses. Two and a half miles up from Beddgelert, the Afon Colwyn is crossed again at Pont Cae Cors, with a couple more bends lifting the road to its summit of 199m at Pits Head. Here it crosses over the little railway, and then the two run side by side on a long straight section above Llyn y Gader into the tiny village of Rhyd Ddu. A large car park next to the station provides for walkers more than passengers, and then as the road curves to the right in the centre of the village, it crosses the Afon Gwyrfai just before the scenic B4418 comes in from the left.
After going through Rhyd Ddu the road narrows for a short distance as it winds down the valley, recrossing the river to reach the northern shore of Llyn Cwellyn. The northern hills of the Snowdon range rise steeply above the road as it once more runs close to the railway, passing Snowdon Ranger station, from where another popular path climbs up to the summit. The road crosses back over the railway at the foot of the lake, and soon the valley is narrowing again, squeezing through the narrow pass at Betws Garmon. This section of the road is hemmed in by stone walls, making it narrow with some tight bends, but before long the hills step back a bit and the road improves a little. After leaving the Snowdonia National Park the railway line and river are both crossed twice in the space of a mile, the second time being on the southern edge of the village of Waunfawr, with the railway taking a different route to Caernarfon.
After a slight kink, the main street through Waunfawr is long and straight, passing a scattering of businesses between the houses. The road then dips down to cross a shallow valley, before climbing slightly over a ridge. From this summit, the flat coastal plain can be seen stretching ahead to the horizon, with the narrow Menai Strait invisible between the fields. Caernarfon is also in view, not too far away, and behind the daunting shapes of the steep sided mountains make a dramatic contrast. The long gentle descent takes it through Caethro where the old informal bypass is crossed at the Caeathro Roundabout, and on the opposite side of the village the A4085 dives under the new A487 bypass. A final dip takes it over the River Seiont on Pont Peblig and so into Caernarfon from the south east. Waunfawr Roads becomes Constantine Road, passing housing estates and the town cemetery, before dropping steeply down between old terraces housing. The route ends on the A4871 at a gyratory system, connected to the Eagles Junction to the east of the town centre.
What is now the A4085 was originally the mainline of the A487. However, after following the route it is obvious that the trunk road along the west coast of Wales had to follow an easier route. The B4410 to the west of the mountains was upgraded to Class I status in 1937, becoming the A4085, and that is the way the trunk road went. In the 1960s the numbering was changed so that the more important road number followed the trunk road and so the A487 and A4085 swapped numbers, giving the A4085 its current route.