Generation of individual and household level population data for 2001 census output areas in the United Kingdom (UK) has been undertaken by the Modelling and Simulation for e-Social Science (MoSeS) node of the UK National Centre for e-Social Science. The MoSeS project outlined an approach for creating an individual level demographic model, which involved selecting sets of Samples of Census 2001 Anonymised Records (SARs) to represent aggregate Census Area Statistics (CAS) populations for 2001. This initialised population would then be dynamically modelled or simulated over time. The datasets created by integrating SARS and CAS form this study. Further information is available from the Modelling and Simulation for E-Social Sciences ESRC Award webpage and the MoSeS project webpage. Users should note that the Principal Investigators did not have access to non-anonymised census data and that the assignment of OAs is based on statistical analysis using published data and the SARS only. The study includes two zip files which unpack with a directory structure based on UK Output Area (OA) and Local Authority District (LAD) codes. oa_isarhp_isarcep_1csv.zip: where the Individual Sample of Annonymised Record (ISAR) data is used to comprise the household population uk_oa_hsarhp_isarcep_1.zip: where the Household Sample of Annonymised Record (HSAR) data is used to comprise the household population. With these data it is possible to reconstruct population estimates for parts of the UK.