The Irish Genealogical Society International (IGSI): http://irishgenealogical.org is the major Irish genealogical society in the USA. One of their projects to make records more accessible is the “Estate Records Index” project.
Estate records are the landlord business papers of the estate and may include lease agreements and rent ledgers. These may document the average tenant farmer, and are an important, although underutilized resource. Prior to the advent of parish registers, the estate records are about the only record available to document the common family.
The difficulty with these types of records is they are scattered at different archives, no index, and often of little genealogically valuable; as not all estate records lists tenants. To find records, you have to know the townland or parish your ancestor lived in, and the landlord’s name. This is where the IGSI “Estate Records Index” is a major contribution.
IGSI has funded a prominent Irish genealogist to go through the estate records housed at the National Library of Ireland in Dublin, and inventory the valuable ones. Most of the volumes are by county and then by civil parish and by landlord/estate. Counties include: Armagh, Carlow, Cavan, Clare, Cork, Donegal, Fermanagh, Galway, Kerry, Kildare, Leitrim, Limerick, Mayo, Monaghan, Roscommon, Sligo, Waterford, Westmeath and Wicklow. Individual estates include: “Lismore – Cork (Bandon Area), Tipperary; and the Inchiquin Peninsula – Clare, Limerick, Tipperary.” The prices are reasonable at between $7-$25 USD. They can be ordered from the IGSI Bookstore link on the website.
I personally use these inventories. Once I have found an estate of interest, then I contact an agent working out of the National Library of Ireland: http://www.nli.ie
The “Estate Records Index” series is worth investing in for your particular county research needs. For any library with an Irish collection, the entire series is worth purchasing.