This chapter explores the spatial variability of infant mortality over the latter half of the nineteenth century within one of the most seemingly uniform rural-agricultural regions – the Fens. The application of a 'regional magnifying glass' to the fenland county of Lincolnshire, bringing smaller spatial units into focus, has reinforced the operation of an 'urban penalty' and helped to establish the existence of a 'fen penalty'. In order to examine the possibility of a 'fen penalty' infant mortality rates (IMRs) were calculated for each registration sub-district within Lincolnshire, again employing the 'conventional' IMR formula. Temporal changes to infant mortality across Lincolnshire were analysed by comparing them graphically. The quinquennial IMRs were then analysed spatially through a series of maps, enabling verification of any associations between certain types of environment – such as 'fen' or 'urban' settings – and the infant mortality level.