Where Can I Find Map Showing Old Irish Estates?

The Lewis topographical may have a descriptive passage about larger estates. I think it is linked to on the os site. The osi maps are a good resource linked already by jd but the full estate won't be clearly identified on them.

mikefoxo wrote: »

I have looked at the website before but does it show the boundaries to old estates?

To a certain extent it does - if you zoom in to your area of interest and then click the 'HISTORIC 6"' button, you will see the first edition of the Ordnance Survey 6 inches to 1 mile map from the 1830s or 1840s. This shows demesnes (rather than estates) with a particular type of shading and the demesne boundaries are thus quite clear. See here for an example:

http://maps.osi.ie/publicviewer/#V1,611952,638128,6,7

It isn't all that easy to see, but if you look closely you will see that in this case the entire townland of Ballyduagh is shaded a little darker than the surrounding fields - this means the entire townland (just over 249 acres) was the demesne of Ballyduagh House.

In case you're not used to looking at these things, the townland acerage always appears just below the townland name on the 6" map (in ARP - acres, roods and perches). The townland is defined on the map by a dotted line, but someone has drawn over that with a red marker at a later stage to make it easier to see. The green over-paint indicates the parish boundary (the civil parish, not the modern religious parish).

Following demesne boundaries by looking at the shaded areas on the 1st edition map is easy enough, unless two demesnes bound each other - there is nothing to differentiate one shaded area from the other and so in these cases it can be difficult to determine where exactly the two demesnes meet.

To be clear, I use the term demesne here to refer to the lands associated with a big house which are used for pleasure grounds, parkland and for the 'home farm' - i.e. that farmland farmed directly under the remit of the landlord. The estate is usually a much bigger area which includes the demesne and all the other lands and buildings which are rented out and are farmed by the leaseholders - this land held by the tenants of the estate is part of the estate but not part of the demesne. The demesne is shaded on the 1st ed 6" map, but the estate isn't.

Depending on which part of the country you are interested in, you may find something of interest here:
http://landedestates.nuigalway.ie:8080/LandedEstates/jsp/

You can also find lots of information in Griffith's Valuation, but it takes some getting used to ...
http://www.askaboutireland.ie/griffith-valuation/

Since Griffith's comes with maps and data in tables, it is very well structured and so can be very helpful - do bear in mind however that it lists only the occupier (i.e. the tenant) and the immediate lessor - i.e. the person the tenant leased the land from. This means that you may find that 20 named people each leased 1 acre from Joe Blogs, and that the same Jow Blogs leased a different 50 acres from the Earl of XYZ, but the data presented won't show you the true picture - that Joe Blogs actually leased 70 acres from the Earl of XYZ and farmed 50 himself while sub-letting 20 out in 1-acre parcels - the connection between the 1-acre tenants and the Earl is invisible because Griffiths doesn't show the full picture, only the occupier and the immediate lessor.

The Manuscripts Room in the National Library of Ireland may also be of help - they hold over 22,000 manuscript maps and the bulk of the collection is hand-drawn estate maps from all over the country, but it can be hit or miss - they may have something on your estate or they may not...
http://www.nli.ie/en/udlist/manuscripts-collections.aspx?article=02547513-4bf9-41cc-9a87-623cf7159106