Llancaiach is a village in Caerphilly county borough, Wales.
It is situated within the CF46 postcode district, which is within the Treharris post town.
CF46 is the only postcode district within the Treharris post town.
The Treharris post town is within the Cardiff postcode area.
Administrative Ward: Nelson
Administrative District: Caerphilly
Country: Wales
UK Parliament: Caerphilly