Tref Alaw takes in the area west and south west of the Llyn Alaw. The community consists of a wide network of dispersed farms, and five settlements. Two small villages, close to each other in the centre of the community area are Llanddeusant and Elim. Llantrisant is a hamlet a mile or so to the south-west of Elim. In the north west is the small village of Llanbabo, and in the far south is the tiny hamlet of Llechcynfarwy, of which the principal building is St Cynfarwy’s Church. At the 2011 census the community had a population of 581.