The name Ratgoed derives from “Yr Allt Goed”, which means the steep, wooded hillside. Ratgoed mine was also sometimes known as “Alltgoed”. The Ratgoed slate workings lie at the head of what was originally called Cwm Ceiswyr but became known as Cwm Ratgoed because of the quarry. It lies north of Aberllefenni and northwest of Corris in, what is now, the Dyfi Forest.

The slate that was quarried at Ratgoed was the Narrow Vein. This runs from south of Tywyn, on the coast, to Dinas Mawddwy about 18 miles inland and follows the line of the Bala Fault. The Narrow Vein was worked along its length at places such as Bryneglwys near Abergynolwyn; Gaewern & Braich Goch at Corris, Foel Grochan at Aberllefenni and Minllyn at Dinas Mawddwy. The slate at Ratgoed dips at 70° to the southeast, the same as Foel Grochan.

Ratgoed was a relatively small working, it was worked from around 1840 until its closure in 1946.