To understand the contemporary politics of prison building we need to think systematically about the capital capacities that have been added the prison estate over time: functionally, geographically and architecturally. ln this chapter I present findings from my review of prison estate transformation in England and Wales between 1990 and 2024. I argue that prison expansionism was achieved in a highly variable fiscal climate where the delivery of new prison places was often precarious, uneven and irregular. Prison establishments continue to expand through a process I characterise here as ‘carceral creep’ with new buildings typically constructed in economically deprived, rural fringe locations. As a result of these siting decisions new prisons in England and Wales are frequently marked by a pronounced double disadvantage. Not only do these buildings hold prison populations characterised by significant race disproportionality, but they tend to be located in rural communities that are themselves less likely to be representative of the country as a whole.