"LLANVAIR-DISCOED, a parish in the upper division of the hundred of Caldicott, county Monmouth, 5 miles S.W. of Chepstow, its post town. It is situated near the forest of Wentwood, and on the road to Usk. The parish includes the hamlet of Dinham, and the remains of Dinham Castle, now a ruin overgrown with wood. The living is a perpetual curacy annexed to the vicarage of Caerwent, in the diocese of Llandaff. The church is dedicated to St. Mary." [Description(s) from The National Gazetteer of Great Britain and Ireland (1868)
Morgan, Charles. Notes on the ecclesiastical remains at Runston, Sudbrook, Dinham and Llan-bedr. Newport : printed for the Monmouthshire and Caerleon Antiquarian Association by Henry Mullock, 1858. 33p.
Church and chapel data from The Religious census of 1851 : A Calendar of the returns relating to Wales, Vol 1, South Wales.Ed. by I.G Jones, & D. Williams. UWP, Cardiff, 1976. The names given towards the end of each entry are those of the informants. Check with Gwent RO to see what extant records are held, and possible names of chapels/churches established after 1851.
Llanvair Discoed Parish consisting of Llanvair Discoed and the hamlet of Dinham; Statistics; Area 1986 acres; Population 103 males, 88 females, total 191
Llanvair Discoed Parish Church Attendance - morning 32 1 service in English Edward Griffiths, Licensed Curate
Dinham Hamlet (Ancient parish now considered only a hamlet..... there is no trace of the church - Lewis 1848)
Family Search have an interactive map called "England and Wales Jurisdictions 1851" showing parish (and other) boundaries with optional background maps such as Ordnance Survey. There is also a Search facility, do read the guidance notes to get maximum benefit from this useful resource. See here for further background information to assist in the interpretation of this data
Kain, R.J.P., Oliver, R.R., Historic Parishes of England and Wales: an Electronic Map of Boundaries before 1850 with a Gazetteer and Metadata [computer file]. Colchester, Essex: History Data Service, UK Data Archive [distributor], 17 May 2001. SN: 4348. Here is a gazetteer/finding aid plus a set of overview maps to accurately identify the position of parishes within the county.
You can see maps centred on OS grid reference ST446924 (Lat/Lon: 51.627674, -2.801742), Llanfair Isgoed / Llanfair Disgoed which are provided by: