The B4509 is a rural B-road in south Gloucestershire. It was originally unclassified but gained its number in the early 1930s.
The road starts on the B4060 at the northern end of the High Street in Wickwar. It heads west then north along The Downs and quickly reaches open country. The road follows a more-or-less straight route and, apart from a tree-lined section past a quarry, runs across open fields. Soon a T-junction is reached on the B4058. There's a short multiplex to the right until a roundabout is reached on the nearside of Charfield and the B4509 turns left to regain its number.
We head northwestwards along the top of a ridge. After passing to the south of Totworth the road starts to descend, with a couple of bends to lessen the gradient. We soon cross the M5 at J14, a diamond interchange with two sets of traffic lights to allow access to/from the slip roads. Our road ends a short distance further on at another set of lights on the A38.
Although this point is the original and current western end of the B4509 the road was extended then shortened again in the interim. In 1935 the road was extended north via a multiplex along the A38 into Stone, then along what was part of the B4068 into the centre of Berkeley to end on the B4066. In more recent years the latter road was moved onto a bypass of Berkeley and the B4509 into town was declassified.