I'm going to give you that one as you have seen the property on the O/S map. It's called the Powder House and it is on Ynys Cyngar in Morfa Bychan,
But what is the history of ‘The Powder House’? The clue is in its name: The ‘Powder’ is Gunpowder.
Gunpowder was regularly used in the Slate Industry. Porthmadog developed rapidly as an important seaport for the export of Slate but for obvious reasons the inhabitants were not keen on the idea of a boat loaded with gunpowder docking close to the centre of their town.
The Powder House
So gunpowder was unloaded at Ynys Cyngar – an isolated spot 2 miles seawards – and then transported to Porthmadog or elsewhere, originally by horse and cart. And that is why this cottage came to be known as ‘The Powder House’