Copyright © 2016 Cambridge University Press. This article uses data extracted from General Register Office mortality registers to map the localization of infant mortality in Dublin city from 1864 to 1910. It traces how late nineteenth-century social inequalities were deeply rooted in the city's history. In order to contextualize the high infant mortality rates, we draw on a range of approaches to provide an overarching view of the causes of the public health problems cities like Dublin experienced.