Porth y Nant is a former late nineteenth century quarry village with two rows of houses, a plas, chapel, school and 'co-op' shop. The three quarries it served have closed but since 1978 the village has been the home of the National Language Centre.

Modern quarrying started in Nant Gwrtheyrn shortly after 1850 to supply granite setts for paving and construction work in large cities. Three quarries were opened - Cae'r Nant (NPRN 40562), Porth y Nant (NPRN 40566) and Carreg y Llam (NPRN 40533). Ships were loaded regularly from purpose built jetties, carrying setts to Liverpool, Manchester and Birkenhead. In 1878, the company erected twenty-four new houses in two rows, with a shop and a bakery; a plas, or mansion (NPRN 16733), was built for the quarry manager.

From a peak between the 1880s and the First World War, the fortunes of the quarries and the village declined overall until final closure of Cae'r Nant quarry around the Second World War. In 1978 a trust purchased the village, which had been empty since 1959, from the Amey Roadstone Company and established the National Language Centre.

B.A.Malaws, RCAHMW, 06 March 2006.