Townland
A townland is the smallest territorial division used for census enumeration purposes in rural areas, each townland is identified by a unique 5 digit code. The boundaries of townlands are displayed in BLUE on rural maps. A townland may be split into urban and rural parts. This occurs when an urban area, a town or village, divides a townland into two or more parts. On the form C these are listed separately under the urban and rural parts of the EA/ED and are distinguished by (PT) after the townland name. These parts are identified by the same townland code in all cases.

Cities/towns
For census purposes, towns fall into two types: those with and those without legally defined boundaries.

Towns with legally defined boundaries
These comprise:
- The five county boroughs (Dublin, Cork, Limerick, Waterford and Galway);
- The five municipal boroughs (Clonmel, Drogheda, Kilkenny, Sligo and Wexford);
- The forty-nine urban districts (e.g., Arklow, Athlone); and
- The thirty-two towns under the towns improvement (Ireland) Act, 1854 (e.g., Greystones, Mullingar).

All of the above have legally defined boundaries (marked in green on enumeration maps) which must be strictly observed during the course of the enumeration.

Where built-up areas have extended beyond the legally defined town boundary, the CSO draws up new boundaries defining the suburban areas of county boroughs and the environs of other legal towns for census purposes. This is necessary for the analysis of population clusters.
CSO extensions to legally defined towns are marked in pink on enumeration maps.

Towns without legally defined boundaries, i.e. Census towns
A Census town is defined as a cluster of 50 or more occupied dwellings, not having a legally defined boundary. Census Town boundaries are determined by the CSO for census purposes only. There were 550 Census Towns in 1996. The boundaries of census towns and the environs of legal towns are denoted in pink on the maps.

Townland: A townland is the smallest territorial division used for census purposes in rural areas. The boundaries of Townlands are displayed in blue on enumeration maps. Townlands are always written on census forms using the 5 digit code specified on form C.