One limitation in the historiography on the 1851 Census of Religious Worship, and indeed for the geography of religion more generally, is that very few detailed maps showing religious patterns have been produced. Hitherto, the best national maps were based on county units only. We have therefore taken this further – within constraints of publication space – by publishing maps here for most denominations as based upon registration-district units, for the whole of England and Wales, and at parish level for certain counties. We have provided national maps for almost all the main denominations, and for the Church of England this has been done with a diversity of possible measures.

Traditional methods of cartographic production are time-consuming and require skills that many historians, and some geographers, do not possess. At registration-district level, maps for the whole of England and Wales would be extremely difficult and time-consuming to draw with traditional methods. We made use of two computer cartographic packages – GIMMS and ARC/VIEW – that allowed us to map registration-district or parish data, and that offered new possibilities in terms of flexibility of data display.

The registration-district boundaries for these maps were derived from the original maps in the published 1851 census. Those census maps were put together for England and Wales, and all boundaries were digitised. County maps showing parishes were based upon those in The Phillimore Atlas and Index of Parish Registers, with adaptations where necessary using other sources and the Ordnance Survey County series dating from the 1930s.