Estates are indexed under the name of the families who owned them at various times rather than by geographical location, but there is an interactive map that takes care of the latter.
About half of the 4,500 indexed properties can be viewed in a gallery of images, some recent, some very old.
LandedEstates.ie is hosted by the Moore Institute for Research at NUI Galway. At its weekend launch, historian and academic director of the database project Professor Gearóid Ó Tuathaigh said it would be of great benefit to both academics and the public.
He said: "This major research resource will be invaluable in assisting and supporting researchers, academics and members of the general public working on aspects of the social, economic, political and cultural life of Ireland, notably rural society from the early 18th century to the eve of the Great War."
It also has obvious genealogical interest. But landed estate resources always come with a caveat: they are rarely of much use if your ancestors were poor (which means that most of us won't find direct details of our families).
Those sub-tenants might also have rented out ever shrinking land areas to a further layer of sub-tenant. The poor rural worker was at the lowest layer, and many of them didn't even have legally enforcable rent agreements.
Even so, these records are interesting in their own right, and provide plenty of social history detail for the period.
In general, estate records contain information relating to the landowner and those lessees closest to the top layers. So if your family was a landowner or member of the gentry (even those who only just squeezed into this category), you may well find some fascinating details among any surviving landed estate records.
The database was created by Brigid Clesham, Marie Boran and Joe Desbonnet.