This article is about Great Moor Street, Bolton.
For the former route in Bedford, see A6172 (Bedford)
The A6172 is allocated to Great Moor Street in the Lancashire town of Bolton.
The road starts at traffic lights on the A575 Bradshawgate in the town centre. It heads west along Great Moor Street, which passes an old school (now flats) and a church and is then lined with shops and offices. The B6204 Newport Street turns left at traffic lights and the road continues on to pass between open space and a car park. It bears round to the right and then ends at the next junction where it becomes Black Horse Street. The other roads here are unclassified.
Although there seems no reason for the A6172 to exist the number is advertised by Bolton MBC. Except for the kink at the western end the road forms part of the original line of the A579 through town (the western end of Great Moor Street is now lost under a car park), although this does not explain why it retained Class I status as maps from the 1980s show the road to be unclassified.
In 2017 the eastern half of the road was made one-way to facilitate the construction of the Bolton Transport Interchange, which makes it even more of a numbering absurdity.