|From:||Castle Street (ST157871)|
|To:||Ton-y-Felin Road (ST158873)|
|Length:||0.1 miles (0.2 km)|
|Now part of:||B4600|
|Route outline (key)|
The A4057 was originally allocated to a short length (under 200 yards) of Bedwas Road in Caerphilly. This cut the southeast corner between the A468 (now B4600) and A469 (now B4263) outside the castle.