19th Century Ordnance Survey Maps online - Clare to Donegal

It is now possible to access the early 19th Century Ordnance Survey maps of counties Clare, Galway, Mayo, Sligo and Donegal online. The service uses technology developed by Rainer Kosbi in association with public library authorities in each county. Access is totally free - without subscription - and the Clare and Mayo maps are closely integrated with their respective websites. You will need to download a plugin for your browser to access these maps, and you will need to use Internet Explorer for the time being.
Digitised versions of historic Ordnance Survey maps of the whole country, including the later 25" maps of 1913, are also available in public library branches throughout the country as a result of collaboration between Ordnance Survey Ireland, the Department of the Environment, Heritage and Local Government and the Public Library Service.