 A flooded pit in the quarry in July 2010 | |
| Location | |
|---|---|
  Dorothea Location in Gwynedd | |
| Location | near Talysarn |
| County | Carnarvonshire (now Gwynedd) |
| Country | Wales, UK |
| Coordinates | 53°1′30″N 4°17′0″W / 53.02500°N 4.28333°W SH 518 503 |
| Production | |
| Products | Slate |
| Type | Quarry |
| History | |
| Opened | 1820s |
| Closed | 1970 |
Dorothea quarry is a disused slate quarry in the Nantlle Valley area in North Wales. It covers a large area near the village of Talysarn and contains three flooded deep lakes.