The B6427 is a short, largely urban road near the south Yorkshire town of Maltby. The road was originally unclassified but gained its number around 1930.
The road starts on an expanse of grass by turning northeast off the A634 and zigzags northwards along Muglet Lane through the former mining community. It's not long before the A631 is crossed at traffic lights. The road is now dead-straight as it climbs out of town, presently reaching open country. Initially the road now remains straight but it starts to bend as it passes a farm and soon enters Braithwell. It ends here at a triangular junction on the B6376 by the 12th-century village cross.