The Ordnance Survey Office was established in 1824 under the direction of Colonel Thomas Colby to undertake a townland survey of Ireland and to map the entire country at a scale of 6 inches to one mile.
The surveyors who undertook this task were also charged with the task of examining individual place-names details and variants to determine a suitable spelling for each name which did not already have a standardised English form and with recording this information in a series of volumes known as Name Books.
Other details were also recorded, such as local monuments, buildings of note, archaeological objects etc. making them a very interesting and useful addition to local information.
Volumes of Letters comprising the correspondence between the field researchers and the Ordnance Survey office were also published and provide further details of interest concerning the history of places countrywide.