This publication maps all 16,000 townlands in the 9 counties of Ulster and the administrative units of church and state into which they have been organised.

The Townland Atlas of Ulster, a new publication from Ulster Historical Foundation, will provide an invaluable guide to the newcomer to the townland system as well as opening up the world of seventeenth-century records to the serious researcher.

No wonder that the Ulster Historical Foundation has described them as a fundamental unit of Irish life. But while a strong connection to townlands still exists in many tight-knit rural communities, their use is no longer as official as it once was.

The Ordnance Survey of Ireland has a really nice application called the Irish Townland and Historical Map Viewer, which will allow you to search for townlands by name and view them on different underlying maps and even compare them with modern aerial photos. How do you use this application?