The 1851 Dublin City Census index was compiled by Dr D A Chart, in the 19th century from the original census records - since destroyed in the 1922 Public Record Office fire. Chart's index, which includes names and addresses of 60,000 heads of household, has now been converted to computerised form by Seán Magee, and is available online exclusively on Irish Origins. The index is accompanied by scanned images of the original 1847 Ordnance Survey Town Plans, to help users identify specific addresses.