Porthgain means 'Chisel Port' in English with the chisel representing the quarrying that once took place here. From around 1850 slate, then brick, and then granite were shipped from the harbour. The crushed granite road stone was dispensed from the massive brick built hoppers, built at the beginning of the twentieth century, directly into small ships alongside Porthgain harbour. These and earlier slate quarrying related structures including the lime kiln, harbour and pilots house can still be seen. Slate was also quarried at Abereiddi and transported along the tram road to Porthgain for export. Mining finally stopped here in the 1930s.

Porthgain is now a very popular tourist centre thanks to a great pub, a super cafe restaurant and excellent art galleries. Add to this the superb location in the heart of the Pembrokeshire Coast National Park and Porthgain has a winning combination. Porthgain was designated as a conservation area by the Pembrokeshire Coast National Park in 1997.