 It takes its name from the river Grwyney (in Welsh, Grwyne) which flows through it into the River Usk.The river Grwyney has two sources, called the Grwyne Fechan and the Grywne Fawr, which both rise in the Black Mountains and converge into one river near Llanbedr before flowing down to the Usk.The community includes the villages of Glangrwyney, Llangenny and Llanbedr.