Caeo (sometimes Caio) is located between Llandovery and Lampeter in the county of Carmarthenshire, South Wales. It sits on the confluence of the Nant Frenna and the river Annell, which runs from its source in the Cambrian mountains before joining the river Cothi near Llansawel.
The towns of Talley and Llanwrda lie to the south, while to the north lies the Caeo Forest and the Cambrian Mountains.
Many Roman remains have been found in the area, as they mined for gold near Dolaucothi, an 18th century mansion. According to history, a battle was fought in Caeo between the Britons and the Romans. Surprisingly the Britons won, as the Roman commander was killed in the fight.