Porthmadog  Porthmadog (; ), known before 1974 by its anglicised name of Portmadoc and locally as "Port", is a Welsh coastal town and community in the Eifionydd area of Gwynedd. Before the re-organisation of 1974 it was in the historic county of Caernarfonshire. It lies east of Criccieth, south-west of Blaenau Ffestiniog, north of Dolgellau and south of Caernarfon, with a community population of 4,185 (2011 census) and an estimated 4,107 in 2018. It developed in the 19th century as a port for slate sent to England and elsewhere, but since the decline of the industry it has become a shopping centre and tourist destination. It is close to Snowdonia National Park and the terminus of the Ffestiniog Railway. The 1987 National Eisteddfod was held in Porthmadog. It includes the nearby villages of Borth-y-Gest, Morfa Bychan and Tremadog. Porthmadog came into existence after William Madocks built a sea wall, the "Cob", between 1808 and 1811, to reclaim a large proportion of Traeth Mawr from the sea for agricultural use. The diversion of the Afon Glaslyn caused it to scour out a new natural harbour which had a deep enough draught for small ocean-going sailing ships, and the first public wharves were built in 1825. Individual quarry companies followed, building a series of wharves along the shore almost as far as Borth-y-Gest, and slate was carted from Ffestiniog down to the quays along the Afon Dwyryd, then boated to Porthmadog for transfer to seagoing vessels. In the second half of the 19th-century Porthmadog was a flourishing port, its population expanding from 885 in 1821 to over 3,000 by 1861. The rapidly expanding cities of England needed high quality roofing slate, which was transported to the new port by tramway from the quarries in Ffestiniog and . The "Ffestiniog Railway" opened in 1836, followed by the "Croesor Tramway" in 1864 and the "Gorseddau Tramway" in 1856, and by 1873 over 116,000 tons (117,800 t) were exported through Porthmadog in more than a thousand ships.