|Distance:||4.8 miles (7.7 km)|
|Meets:||A55, A5153, A5, A5025|
|Route outline (key)|
The B4545 connects the town of Holyhead to the village of Valley via a looping route (the A5 between the two places is more direct) through Trearddur and Four Mile Bridge. The road was originally unclassified but gained its number in the early 1930s.
Starting from junction 1 of the A55 in Holyhead, the B4545 passes through residential streets to the Kingsland area of the town, before reaching a newish roundabout junction with the short A5153, which leads back to the A55 at junction 2 and then on to the A5.
Passing fields and a golf course now, the road has a posted speed limit of 40mph. Soon, however, it returns to a 30mph limit as houses are reached at Trearddur, the bungalow suburbs of which go on for a while before the road reaches the beachside area and a car park. There are suburbs on the other side of the village too and they don't really stop before Glan-traeth. After that is a mixture of housing and fields and this gets another 40mph limit.
A view of the Cymryan Strait appears on the left. This is what separates Holy Island from Anglesey. Another 30 mph limit appears for the village of Four Mile Bridge. The name refers not to the length of the bridge, but to the fact that it lies approximately four miles from Holyhead. The bridge itself is in fact only 120 m long and at low tide it is actually possible to wade across the strait in places. Beyond the bridge is another part of the village. Subsequently we reach the outskirts of Valley.
The old road is diverted ahead, as the A55 North Wales Expressway now cuts it in half. Our road now crosses the A55 on a flyover with no junction. A small new roundabout joins another local road. We go through Valley proper now and a level crossing and the village's small station are passed. The road ends at a traffic-signalled crossroads, the left and right turn being the former main route to Holyhead, the A5, and the straight-on route becoming the A5025.