Penmachno quarry
| View of the Penmachno quarry from the north-west, in 2007 | |
| Location | |
|---|---|
| Location in Conwy | |
| Location | near Cwm Penmachno | 
| County | Conwy County Borough | 
| Country | Wales, UK | 
| Coordinates | 53°00′18″N 3°51′35″W / 53.005111°N 3.859802°W grid reference SH7522046962 | 
| Production | |
| Products | Slate | 
| Type | Quarry | 
| History | |
| Opened | c.1818 | 
| Active | c.1818-1909; 1909-1962 | 
| Closed | 1962 | 
The Penmachno quarry (also known as Cwm Machno quarry, Rhiwfachno quarry, or Tan-y-Rhiw quarry) was a slate quarry near Cwm Penmachno, Conwy, North Wales. It was directly below the Rhiwbach Quarry. It was worked between 1818 and 1962.