At the end of the nineteenth century it was the world's largest slate quarry; the main pit is nearly 1 mile (1.6 km) long and 1,200 feet (370 metres) deep, and it was worked by nearly 3,000 quarrymen.

[2] The quarry is significant in the history of the British Labour Movement as the site of two prolonged strikes by workers demanding better pay and safer conditions.

[4] Historically, most accounts of the strike have mainly looked at its effects on male workers, owners, management, economy, and trade unions.

They aim to shed light on the wider community's experiences during the strike, paying special attention to the often ignored roles and perspectives of women.

[5] In the longer term the strike lessened confidence in the Welsh slate industry, leading to declining orders and greater unemployment.

[10] In July 2021 the slate landscape of Northwest Wales, including Penrhyn quarry, was inscribed as a World Heritage Site by UNESCO.