PRONI has put the Griffiths revaluation records from the 1860s to 1930 on-line on their site (free). For those unfamiliar with them, they are the continuation records of the original Griffiths Valuation (1847 – 1864), and use the same plot numbers and townlands. You can use these records to see when someone acquired or disposed of a property, when they died (eg the occupant will change to “reps of…”), plus other changes such as purchase (“in fee”), Land Act Purchase “L.A.P” or demolition etc. The date of most changes is noted in the remarks column for each property. Different coloured inks were used for different years.
The PRONI records only cover the 6 counties of what is now Northern Ireland. The equivalent records for the Republic remain in paper form and can be accessed in the Valuation Office, Dublin.http://www.proni.gov.uk/index/search_the_archives/val12b.htm