|Distance:||10.4 miles (16.7 km)|
|Meets:||A458, A490, A483|
|Route outline (key)|
The B4392 is a rural B-road in eastern Montgomeryshire.
The road starts on the A458 at Cyfronydd and heads northeast, climbing steadily as it does so to a summit of over 700 feet near Stonehouse. It then descends a small valley to reach the A490 at Groes-lywd. The A-road is crossed at a staggered crossroads.
Shortly afterwards the road reaches Guilsfield, the only settlement of any size en route. In the centre of the village it reaches a T-junction where the other two directions are also numbered B4392. The road to the right is a spur, reaching the A490 about half a mile south of Groes-lywd; the road to the left is the mainline. In fact, the road we have just travelled on was unclassified in 1922 (so the "spur" was actually the mainline); the road was extended west to Cyfronydd in 1935.
Continuing northeast the B4392 runs parallel to what used to be the Guilsfield Arm of the Montgomery Canal, now barely in water. It crosses the canal twice, although both bridges have been removed and the watercourse culverted. The Montgomery Canal itself (also disused - but not as disused) is then met and this is followed to Arddleen. The B4392 ends on the far side of the village at a T-junction on the A483.