Area 278 km2
ISO 3166-2 GB-CAY
ONS Code 00PK
Population (Est. 2004) 170,700
Caerphilly [county borough] is a local government principal area in southern Wales, straddling the boundary between the traditional counties of Glamorgan and Monmouthshire.
Its main town is Caerphilly. Other towns in the county borough are Bedwas, Risca, Ystrad Mynach, Newbridge, Blackwood, Bargoed, New Tredegar and Rhymney.
The county borough was formed on April 1, 1996 by the merger of the Rhymney Valley district of Mid Glamorgan with the Islwyn borough of Gwent.