Nant Ffrancon Anti-invasion Defences

Cadw's description

Summary description and reason for designation

The following provides a general description of the Scheduled Monument.

The monument consists of anti-invasion defences, dating to the early period of World War II (AD 1940-41), that formed part of Western Command Stop Line No. 23, which ran from Bangor to Porthmadog. The defences are located at the S end of Nant Ffrancon, where they defend the strategically important Ogwen Pass between Bethesda and Capel Curig. The surviving structures include two pillboxes, including one that defends Llyn Ogwen, six spigot mortar emplacements, three infantry positions and an incomplete alignment of eight anti-tank blocks. The rectangular pillboxes are built of concrete and faced with local stone. The spigot mortar emplacements consist of concrete pedestals mounted on circular foundations. They feature domed tops with inset stainless steel pivots. The infantry positions are built from dry stone.

The monument is of national importance for its potential to enhance our knowledge of World War II anti-invasion practices. The monument is well preserved and has a collective group value. It is an important relic of actions taken against the perceived threat of a German invasion from Ireland. It retains significant archaeological potential, with a strong probability of the presence of associated archaeological features and deposits.

The scheduled area comprises the remains described and areas around them within which related evidence may be expected to survive.
Area 'A' is centred on Item 'A' (NGR SH 65487 60480). The scheduled area is circular and measures 15m in diameter. Area 'B' is centred on Item 'B' (NGR 64783 60577). The scheduled area is circular and measures 20m in diameter. Area 'C' is centred on Item 'C' (NGR 64898 60484). The scheduled area is circular and measures 8m in diameter. Area 'D' is centred on Item 'D' (NGR 64755 60404). The scheduled area is rectangular and measures 27m N-S by 10m transversely. It is bisected by a road, which is excluded from the scheduled area. Area 'E' is centred on Item 'E' (NGR 64660 60329). The scheduled area is circular and measures 8m in diameter. Area 'F' is centred on Item 'F' (NGR 64646 60365). The scheduled area is circular and measures 8m in diameter. Area 'G' is centred on Item 'G' (NGR 64640 60405). The scheduled area is circular and measures 8m in diameter. Area 'H' is centred on Item 'H' (NGR 64371 60555). The scheduled area is circular and measures 8m in diameter. Area 'I' is centred on Item 'I' (NGR 64243 60729). The scheduled area is circular and measures 8m in diameter. Area 'J' is centred on Item 'J' (NGR 64210 60730). The scheduled area is circular and measures 8m in diameter. Area 'K' is centred on Item 'K' (NGR 64129 60944). The scheduled area is rectangular and measures 24m N-S by 18m transversely.