The Society aims to study local history and heritage in the area of the old parish and urban district of Gelligaer in north east Glamorgan, which includes modern communities such as Pontlottyn, Tirphil, Brithdir, Bargoed, Hengoed, Ystrad Mynach, Trelewis, Bedlinog, Fochrhiw and Deri as well as the village of Gelligaer itself. The Society promotes this by arranging lectures, discussions and field meetings to heritage sites as well as encouraging research.
The Society meets on the last Wednesday of each month during the winter months at Llancaiach Fawr, where a talk is given (see Events tab above). The talks are not necessarily restricted to the subject of Gelligaer; one recent talk being on the Pirates of the Bristol Channel. The society has, since 1964, periodically published a journal  see Publication.