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
Places, villages, farms etc., within Brecon St Mary parish as shown on the parish map on the CD of Historic Parishes of England and Wales: an Electronic Map of Boundaries before 1850 with a Gazetteer and Metadata [computer file]. (Kain, R.J.P., Oliver, R.R.). (Extracted by John Ball)
- St Mary  - Barracks, Brecon, Brynich, Hospital(NB - St Mary's is shown as a chapelry to St John's on the source gazetteer).
You can see pictures of Brecon, St Mary which are provided by:
You can see the
administrative areas in which Brecon, St Mary has been placed at times in the past. Select one to see a link to a map of that particular area.
Plan of the chapelry of St Mary's within the parish of St. John the Evangelist in the County of Brecon - on the People's Collection Wales site
You can see maps centred on OS grid reference SO045286 (Lat/Lon: 51.947669, -3.390884), Brecon, St Mary which are provided by: