|Length:||5.4 miles (8.7 km)|
|Meets:||A487, A4085, A498|
|Old route now:||A487|
|Route outline (key)|
The B4410 is a short rural B-road in North Wales.
It starts on the A487 at Tan-y-bwlch in the Vale of Ffestiniog, not far from Maentwrog, and heads northwest through the woods to Llyn Mair, running along the shore of the lake. It then goes past the drive to Tan-y-bwlch station on the Ffestiniog Railway before going under the line.
After climbing onto the moors, the road goes through Rhyd and continues to ascends steeply before bending sharply left and descending onto the Traeth Mawr. It reaches the A4085 at Garreg and crosses it at a staggered crossroads. The road then continues west across the completely flat land. It runs adjacent to the Welsh Highland Railway for half a mile and shares a bridge with it across the River Glaslyn. Immediately afterwards the B4410 bends right and goes over a level crossing.
The road ends shortly afterwards on the edge of the Traeth Mawr, at a T-junction on the A498.
All of the above was unclassified in 1922. Originally the B4410 ran from the A499 at Llanwnda south via Penygroes, then east to end on the A498 at Tremadog. The road was then extended via a lengthy multiplex along the A498 across the Traeth Mawr to Garreg.
In 1935, the entire original section of the B4410 was upgraded to Class I status, becoming the A4085. At more-or-less the same time, the road was extended east from Garreg to Tan-y-bwlch, thus giving the road its current route.
In the 1960s the A487 and A4085 between Penrhyndeudraeth and Caernarfon swapped numbers, so the former took over the ex-B4410. Sections of this road, particularly near Caernarfon, have since been bypassed but the route remains the same.