Origin of townland system The earliest reference to townlands as a unit are in 11th century pre-Norman legal documents referring to grants of bailte to monasteries. The term baile has a variety of related meanings in Irish, such as "home" (the basic meaning), "village" (sráid-bhaile, literally "street-town", or "town" (baile mór, literally "big town"). In the context of placenames, the most accurate translation might be "the land belonging to a particular home or farmstead". The modern Irish for townland is baile fearainn, literally "a home of land".
The term townland is a standardised form, often replacing earlier local terms such as tate or ballyboe (in Fermanagh and Monaghan), cartron (in Connacht) or ploughland. These terms represent a variety of native land divisions, varying in name from one part of the country to another, and forming a hierarchy of sizes.
The nineteenth-century surveyor Thomas Larcom, who was the first Director of the Irish Ordnance Survey, summarised the hierarchy as follows:
10 acres - 1 Gneeve; 2 Gneeves - 1 Sessiagh; 3 Sessiaghs - 1 Tate or Ballyboe; 2 Ballyboes - 1 Ploughland, Seisreagh or Carrow; 4 Ploughlands - 1 Ballybetagh, or Townland; 30 Ballybetaghs - Triocha Céad or Barony.
(A complicating factor was that in Gaelic times, land was measured in terms of its economic potential rather than in fixed units of measurement: by the number of cattle that an area of pasture land could support, or by the time taken to plough an area of arable land. Therefore the size of an "acre" in this system could vary enormously depending on the quality of the land.)
** Under English rule Townlands were first named and their boundaries defined under the English legal system during the process of plantation. (Robert Adair's lands).The unit from the hierarchy of land divisions that was chosen to represent a "townland", however, might vary from county to county; in Fermanagh and Monaghan, the tate was chosen, resulting in relatively small townlands, while in other areas, larger units such as ploughlands were chosen, resulting in larger townland units.
As explained previously, townland size was often determined by the fertility of the land, thus townlands in high quality land tended to be smaller, while townlands in mountainous or bog areas tended to be much larger in size. In many areas of Norman settlement, townland boundaries tend to follow field or individual property boundaries and may reflect the holdings of monasteries or churches or the boundaries of commonage. In these areas, townlands often have apparently irregular boundaries and are of small size. In contrast, townlands in areas of traditional Gaelic settlement tend to be larger in area and usually have apparently regular boundaries determined by streams, rivers or roads.