"KILGWRRWG, (or Kilgooroog), a parish in the upper division of the hundred of Ragland, county Monmouth, 5 miles N.W. of Chepstow, and 6 S.E. of Usk. The parish is of small extent and wholly agricultural. The living is a perpetual curacy in the diocese of Llandaff, value £57, in the patronage of the Archdeacon of Llandaff." [Description(s) from The National Gazetteer of Great Britain and Ireland (1868)
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.
Kilgwrrwg Parish; Statistics; Area 659 acres; Population 86 males, 68 females, total 154
Kilgwrrwg Parish Church - Erected about 180 years, 1671 Attendance - morning 25, afternoon 35 No Sunday scholars 1 service in English Informant; James White, Registrar
Zion Bible Christians Erected 1842 Attendance - morning 40, evening 60 George M (?), Local Preacher and Steward, Micham, Kilgwrrne Hill
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 ST471982 (Lat/Lon: 51.680059, -2.766508), Cilgwrrwg / Kilgwrrwg which are provided by: