In 1941, when threat of invasion was at its highest, a network of defensive positions was established around the coast. Their hexagonal shape was reminiscent of the small boxes used for dispensing medicene. Hence, they became known as pillboxes.
The pillboxes at Ynyslas would have been manned by soldiers from the No 15 and No16 Platoon of the 1st Cardiganshire Battalion, Home Guard.
No 15 Platoon covered Taliesin and Glandyfi, while No 16 Platoon covered Borth, Llandre and Dolybont.
This pillbox is likely to have been demolished at the end of war as apart of the restoration of the land to its private owners.
See story: http://peoplescollectionwales.co.uk/Story/481-from-ynyslas-to-the-stars