Trebanog is a village in the Cymmer electoral ward lying on the southernmost outskirts of the Rhondda Valley, Rhondda Cynon Taf, Wales, located off the A4233 road between Porth the unofficial capital of the Rhondda, and the town of Tonyrefail which is at the head of the Ely Valley. Trebanog is an outlying district of the community of Cymmer, which itself is a district of the town of Porth. It is neighboured by the settlement of Edmondstown (a district of Penygraig) and it is located within the historic county of Glamorgan.