The first state census undertaken in Ireland was enumerated in 1821 and every decade thereafter until 1911. However, the returns for 1861-1891 were pulped in the early 20th century, and in 1922 the majority of returns for 1821-1851 were destroyed in a fire at the Public Record Office of Ireland in Dublin during the Irish Civil War. The only complete surviving census returns for all Ireland date from 1901 and 1911. The destruction of the 19th-century records has created a huge gap for those researching their Irish roots.
However, since 1922 Irish genealogists have been seeking out sources that can act as substitutes for the lost census returns. The criteria are pretty broad: if a source contains a list of names with identifying information
