Area shown on Maps
The area shown on the 1842 maps differs from the current area of Co. Clare.
The parish of Clonrush and part of the parishes of Kilbarron and Iniscaltra were in County Galway in 1842, and so are not included in these maps. They were added to the county after the boundary surveys of the 1850s. The townlands concerned are as follows:

Clonrush Parish: Ballinrooaun, Ballyglass, Ballyhinch, Ballynakillew, Ballynamona, Bargarriff, Birchpark, Boleynagoagh North, Boleynagoagh South, Cappagha, Cappantruhaun, Cartron, Clonrush, Cloonmohaun, Cloonoolia North, Cloonoolia South, Cregg, Derrainy, Drummaanadeevan, Drummaan East, Drummaan South, Drummaan West, Furnace, Garraun, Garryeighter, Gortnascreeny, Gweeneeny, Kilcooney, Kilkittaun, Lakyle, Meelick, Rinskea, Tintrim, Whitegate.
This parish includes the town of Whitegate.

Kilbarron Parish: Islands in Lough Derg: Illaunmore; five other islands.

Iniscaltra Parish: Bohateh North, Bohateh South, Cappaduff, Cloonamirran, Cloontyconnaught, Curratober, Derroran East, Derroran West, Derrycon Lower, Derrycon Upper, Dooros, Glenwanish, Iniscaltra, Kilrateera Lower, Kilrateera Upper, Knockaphort, Magherareagh, Middleline North, Middleline South, Mountshannon, Sellernaun East, Sellernaun West, Woodpark.

This part of Iniscaltra includes the town of Mountshannon.

Towns
The term 'Town' refers to groups of twenty or more contiguous houses.

Markings on Maps
Straight single or double lines forming large rectangles are caused by the joining together of the various sheets of the original maps.
Other straight lines may indicate rips and folds in the original maps.
Undulating light brown lines indicate where the coloured boundaries of parishes and townlands have seeped through from an adjacent map sheet during storage.

Monument symbol positioning
We are aware that some of the co-ordinates for monument symbols are inaccurate. The co-ordinates are derived from data compiled by the Department of the Environment, Heritage & Local Government, which has kindly allowed us to use this information on our system. The Department is currently undertaking a review of every monument in the country to correct these known inaccuracies.