In 1922, millions of Irish census records were lost when the Public Record Office of Ireland was destroyed in a catastrophic explosion and fire. This presents a major obstacle for anyone tracing their Irish ancestors prior to 1901. Now, The National Archives is a leading partner in the Virtual Record Treasury of Ireland (VRTI), a project working to track down surviving copies of the records destroyed a century ago. Family history specialists Jessamy Carlson (The National Archives) and Brian Gurrin (VRTI) explain how family historians can use newly identified census transcripts, and earlier census records in the VRTI, as well as how to combine them with other collections, to help you find your Irish ancestors.