Prison History: How to use the Census for Prisons Research. “Like for households, those who resided in state institutions, including prisons, had to be described and enumerated in the official census returns. In 1841, the process was handled by the local enumerators, and not all public institutions were included. In 1851, arrangements were made in advance for such institutions to send returns directly to the Census Office and, in consequence, coverage was much more comprehensive. The idea of a list of everyone resident in a prison – staff and prisoners alike – sounds like a gold mine for family historians and prison researchers alike. In many respects it is, as I will explain. First, though, it is important to point out that the census has one major limitation: it captured the population on a single night and only once every ten years.” This is for the UK.