|Length:||1.8 miles (2.9 km)|
|Meets:||A469, B4254, A472|
|Route outline (key)|
The B4252 is a short, largely urban B-road in the Rhymney Valley.
It starts on a spur of the A469 in Pengam and heads south along the valley, parallel to two other A-roads (the A469 and A4049). To begin with it is the dominant partner in a useless multiplex with the B4254, a situation that can be explained by the fact that the B4252 came first and was not renumbered when the B4254 was extended east.
Continuing south, the B4252 passes through Fleur-de-Lys before going under the Hengoed railway viaduct (which is now part of the National Cycle Network as the line closed in the 1960s) and ending at traffic lights on the A472.