A great deal of Irish census information survived thanks to the Irish pension system. Introduced in 1909, it required all applicants to prove that they were at least 70 years old. As civil registration of births in Ireland only began in 1864, officials used the 1841 and 1851 census returns as evidence to make their claim. The information they gathered was incorporated into the pension application records.
Most of the 1841 and 1851 Irish Census Search forms contain the name of the applicant, the current address of the applicant (often care of a local official or business), the name, age and address of the applicant in the 1841 or 1851 census, the names of the applicant’s parents, and the names and ages of other family members recorded in the 1841 or 1851 census.