Church and chapel data from The Religious census of 1851 : A Calendar of the returns relating to Wales, Vol 11, North Wales. Ed. by Ieuan Gwynedd Jones, UWP, 1981. The names given towards the end of each entry are those of the informants.
Parish statistics; Area 6760 acres; Population 378 males, 340 females, total 718
- Tregynon Parish Church Attendance - average - 90 - 150 Service in English " In consequence of the parish being served with another there is but one service - Morning and Evening - alternately each Sunday" R W Morgan, Perpetual Curate
- Tregynon Chapel, Calvinistic Methodist Erected before 1800 Attendance - morning 27 + 28 scholars, evening 60 Richard Tilsley, Deacon
- Gerezim, Calvinistic Methodist Erected 1840 Attendance - morning 51 scholars, afternoon 62, evening 48 Owen Brown, Trustee, Argoed