First Edition OS maps, 1830s

The Ordnance Survey (OS) was set up in Ireland in the autumn of 1824, with the aim of providing maps for the valuation of Ireland to support the local taxation system. It was carried out by Royal Engineer officers and three companies of sappers and miners, under the command of Colonel Thomas Colby (1784-1852). Civil servants and scholars were assigned to help with sketching, drawing and engraving maps and writing accompanying descriptive accounts.

The survey began in 1830 with the city of Derry, and the first base line, from which most subsequent maps of Ireland have been produced, was an 8-mile stretch between Magilligan and Ballykelly.

The survey at 6 inches to the mile provided the valuation office with maps on a scale large enough to show townland boundaries. Ireland was the first country to be completely mapped on such a large scale. This first series of maps, the First Edition 6 inches to the mile series, was of outstanding quality, including administrative boundaries, topographical features, vegetation features, agricultural and industrial features, settlements, transport routes and place names. The mapping of woodland was detailed, with different symbols, and use of those symbols, to depict the differences between conifer and broadleaved woodland, mature and young woodland, plantation and natural woodland, and different types such as parkland and scrub.

For the purposes of the inventory of ancient and long-established woodland, where woods have their own name on this map series, separate from that of the townland or estate, then it is suggestive of longer continuity of woodland cover.

A record was also made of the woodland type on this map series, whether broadleaved, conifer, mixed, scrub, or parkland. Woods shown as conifer or mixed must be plantation, and this information was used in the classification of the woods, in conjunction with other information.

These maps are available to look at in the Public Record Office, Northern Ireland (PRONI). Local OS maps may be available in libraries. PRONI and Ordnance Survey Northern Ireland are in the process of digitising old OS maps to be available on the internet.