MIs held at Powys Archives - Breconshire
Welsh Gravestone Inscriptions and Graveyard Welsh - guides to interpreting Memorial Inscriptions.
Graveyard Surveys - Over the past twenty years, Gareth Jones has produced surveys of the graveyards of over fifty churches and chapels. Each survey is reproduced on A4 sheets with introduction, full inscriptions, and indexes to personal names and place-names. Some of these surveys are large, e.g. the parish churchyards at Defynnog, Llywel, and Ystradgynlais, and Tynycoed Chapel, Abercrâf. Other Breconshire parishes covered include Llandeilo'r Fân, Llanfihangel Nant Bran, Merthyr Cynog, Llandyfaelog, Llanfihangel Fechan, Battle, Brecon (St David's & St John's), Aberyscir, and Trallwng. For free advice, a full list of surveys, and charges, contact Gareth Jones at garethjones113[at]yahoo.co[dot]uk.
The section of The National Gazetteer (1868) relating to Brecknockshire - transcribed by Colin Hinson.
Tallis's Topographical Dictionary of England and Wales, published in 1860 in six vols, editor E. L. Blanchard. See Welsh Family History Archive for all the excellent county maps (showing the hundreds) and the alphabetical gazetteer. From the preface: "In the following pages will be found fully described the past history and present aspect of every place of any significance in England and Wales, forming a work of permanent importance to the commercial world, of ready service to the tourist of the day, and of constant interest to the general reader, who may derive from this source a large supply of entertainment, as well as of information for the amusement and instruction of a leisure hour."
Here is a map of the county with parish boundaries superimposed. Click on a section to bring up a bubble containing the parish name plus a link to its page
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
Map of Breconshire on Breconshire Local & Family History Society website
Breconshire and Radnorshire with their hundreds by Thomas Taylor, 1718 - on the People's Collection Wales site
Map of Breconshire parishes on Powys FHS Brecknock Group website
Breconshire Old Maps
Welsh county maps on the UK Genealogy Archives site
Cambridge University Library's collection of John Speed's County Maps published circa 1610, include his detailed map of Breconshire.
Details of various maps available at Powys Archives
An exceptionally useful set of maps showing parish boundaries, on a one inch to the mile scale, was produced in 2001 by Kain, R. J. P. and 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. See here for current availability.