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Large Scale Ordnance Survey maps of Ireland in the Map Library

Large scale Ordnance Survey mapping of Ireland was begun in the late 19th century and the way that it is organised has changed enormously since then. Until the Second World War, individual counties were surveyed separately. 

Each county had its own sheet numbering and revision and updating was done by county. This reflected the system used in mainland Britain at the time; before 1922 mapping of the whole of the British Isles was produced by the Ordnance Survey of Great Britain and Ireland.

After the political division of Ireland in 1922 two organisations, the Ordnance Survey of Northern Ireland and the Ordnance Survey Office (Dublin) became responsible for mapping Ireland. After the War the National Grid system was introduced. The National Grid for Ireland is separate from the National Grid for Great Britain (with which you may already be familiar).

Because of these changes, the County Series and National Grid Series maps have to be referred to, and ordered, quite separately. In addition, the National Grid mapping for Northern Ireland and for the Republic of Ireland do not follow the same system. This guide deals with the largest scale mapping of Ireland, at scales of six inches to the mile (approximately 1:10 000) and larger.

1. The County Series maps of Ireland (mid 19th century to World War II)

The County Series covers the whole of Ireland until World War II. In format, design and content the sheets are similar to the Great Britain County Series. Samples of the various sheets can be seen at the front of the volume of indexes at Maps Ref. Z.5a (13), or in A description of the Ordnance maps of Northern Ireland (1959) at Maps Ref. Z.5a (12).

The County Series maps were produced at two main scales. The 1:2500 scale plans (approx. 25" to 1 mile) were the largest scale plans published by the O.S. apart from town plans (OSTs: see below) and cover the whole of the British Isles except for mountain and moorland areas. Those published for Ireland, unlike those for Great Britain, do not always show plot numbers.

The 1:10 560 scale (6" to 1 mile) is the largest to cover the whole of the British Isles. Early editions of the Irish maps at this scale do not show contours. Acreages of townlands are shown on Irish maps at this scale.

1.2 Finding the right sheet

Use the index at Maps Ref.Z.5a.(13.). To order a 6" to 1 mile map you will need to know the County name and the sheet number; for 25" to 1 mile maps you will also need a subsheet number. The index indicates which areas are covered at the larger scale and which are only covered at 6" to 1 mile. When ordering First Edition 1:2500 sheets for Dublin County the parish name must be quoted. To find the parish name, see the card index in the Reading Room on top of the microfiche cabinets.

1.3 Editions

6 inch to 1 mile maps: the Irish 6" or Townland Survey was the first large scale series published by the Ordnance Survey in the British Isles. The first editions were published from the 1820s to the 1840s, well before their counterparts for Great Britain. The Map Library Catalogue gives dates of editions for each county.

25 inch to 1 mile maps:Apart from County Dublin (1873-70), all First Editions of the 25 inch scale were published in the 1890s or early 1900s, later than the equivalent maps for Great Britain. There is a list of editions of the 25" scale maps in the Public Service Guide (blue binders behind the Reference Enquiry Desk) under Ireland. In addition, the Map Library Catalogue contains entries for each individual county survey at this scale.

1.4 Ordering

All the Irish sheets are stored in the basement, mainly in volumes; they have to be requested using the ABRS.

1.5 Obtaining copies

The sheets are very large and generally bound in volumes, so ordinary photocopying is not normally possible. See the leaflet The British Library: reproductions for details of how sheets can be copied.

2. Ordnance Survey Town Plans (OSTs)

OSTs were published for larger towns and cities at 1:1056 (5' to 1 mile) from around the 1840s. They were the largest scale OS plans published for Ireland. Samples can be seen on p.33 of J.H. Andrews History in the Ordnance map: an introduction for Irish readers (1993), shelved at Maps Ref. G2a. Ireland. (6).

2.1 Finding the right sheet

First, consult the catalogue under the name of the town that you're looking for to find the shelfmark (Maps OST, and then a number). Nearly all Irish OSTs are contained in single volumes, so you can order the whole thing rather than having to identify a particular sheet. The only exceptions are Dublin 3rd and 4th editions (OSTs 258 and 259); an index for these is filed in the grey drawers to the left of the Issue Desk.

2.2 Editions

The Map Library Catalogue lists all editions of any town plan; just look it up under the town name. In addition, there is a list of all towns mapped with dates of publication in the Ordnance Survey Catalogue at Maps Ref. Z.5a. (15), and an alphabetical inventory of all OST editions in the Public Service Guide (held behind the Reference Enquiry Desk) under the heading Town Plans.

2.3 Ordering

For most OSTs you will require only the OST number; for later editions of Dublin you should put a sheet number as well.

2.4 Obtaining copies

The sheets are very large and generally bound in volumes, so ordinary photocopying is not normally possible. See the leaflet The British Library: reproductions for details of how sheets can be copied.

3. Modern large scale plans (post World War II)

Northern Ireland and the Irish Republic have different systems of sheetlines for their modern large scale map series. Both are related to the Irish Grid, (which is a grid referencing system similar to the National Grid in Great Britain, covering the whole of Ireland) but it does not form the basis of either sheet numbering system.

3.1 Northern Ireland

The maps for Northern Ireland are sometimes, confusingly, referred to as the Irish Grid Series. Samples of the sheets can be seen in A description of the Ordnance map of Northern Ireland (1959) at Maps Ref. Z5a. (12.).

Maps are produced at 1:10 000, 1:2500 and 1:1250 scales; the largest scale covers only towns and cities. Some rural areas are covered only by the 1:10 000 scale, which is also the largest scale to show contours.

Finding the right sheet

Use the graphic index from the open access drawers in the catalogue area of the Maps Reading Room. You only need to find a sheet number; there is no need to put the county name for maps in this series.

The same numbering system applies to all three available scales. The six inch maps are referred to simply by sheet number, eg., Ballymena is on sheet 67. The 1:2500 plans require a sheet and a subsheet number; Ballymena railway station is on sheet 67 - 7. The 1:1250 scale sheets are subdivisions of the 1: 2500 into NE, NW, SE and SW quadrants.

Editions

There is no list of editions available owing to the large number of sheets and variety of edition dates. The 1:1250 scale for towns and cities was introduced in 1955. As for the National Grid (Great Britain) series, it is advisable to order both the 1:2500 and 1:1250 scales for towns and cities.

Ordering

Sheets are stored in the basement and must be ordered using the ABRS.

Obtaining copies

One A4 extract from any sheet can be supplied. If a larger portion is required written permission must be obtained from the OSNI, unless it is for a court case. If full-sized copies are required please see the leaflet Reprographic Standard Services (in the leaflet rack next to the Issue Desk). When the maps are to be used for a court case a written statement should accompany the completed application form. For more details see the OS leaflet Copying of maps held in public libraries (displayed by the microfiche readers) or contact Ordnance Survey Copyright and Legal Affairs on 01703 792302.

3.2 Republic of Ireland

The large scale plans of the Irish Republic are similar to those for Great Britain and Northern Ireland, but there are some important differences. The sheet numbering system is completely different from Northern Ireland and Great Britain and is unrelated to the Irish Grid which covers both Northern Ireland and the Irish Republic.

3.2. (i) The different scales

The 6" and 25" County Series maps described above were revised and reissued until well after WWII, unlike those for Great Britain. Mountain and moorland areas were only ever covered at the 6" scale. . There is no modern 1:10 000 or 1:1250 series. However the 6" County Series mapping was continued until well after the war. There are also some post war 1:1250 sheets, and there is a modern equivalent to the latter at 1:1000 for large towns and cities. Modern coverage at 1:2500 is incomplete as the whole of the Republic has not yet been resurveyed; for some areas the County Series is all that is available.

3.2. (ii) Finding the right sheet

"Irish Grid" indexes are on open access, in the grey drawers to the left of the catalogue area in the Maps Reading Room. The sheet numbers are not actually related to the Irish Grid. Each sheet has its own individual number, but it is also necessary to give the county name as these sheets are filed by county.

The 6" and the 1:1250 sheets are on the same sheetlines as the pre-war County Series. For instructions on locating these, see section 2.2 above.

1:1250 sheets cannot be ordered on the ABRS, only on paper tickets. Please ask Issue Desk staff for further details.

3.2. (iii) Editions

There is no list of editions owing to the large number of sheets and variety of edition dates. For many sheets only one edition will be available.

3.2. (iv) Ordering

All sheets are stored in the basement and have to be ordered using the ABRS.

Because of the incomplete coverage of modern Irish mapping it is best to order the County Series sheets even if you are looking for the most modern maps available.

3.2. (v) Microfiche

Many of the modern 1:2500 and 1:1000 sheets have been published in the form of microfilm aperture cards, the Irish equivalent of the SIMS for Great Britain. Earlier plans in sheet form are available for some areas.

These sheets are referred to in the same way as the sheet maps. You must find the sheet number from the "Irish Grid" indexes. You also need to know the county, as they are arranged in the drawers in county order.

3.2. (vi) Obtaining copies

One A4 extract from any sheet can be supplied. If a larger portion is required written permission must be obtained from the OSI, unless it is for a court case. If full-sized copies are required please see the leaflet Reprographic Standard Services (in the leaflet rack next to the Issue Desk). When the maps are to be used for a court case a written statement should accompany the completed application form.

4. Further reading

ANDREWS, John H. History in the Ordnance map: an introduction for Irish readers. Dublin: Ordnance Survey of Ireland, 1974.

FERGUSON, Paul Irish map history: a select bibliography of a secondary works 1850-1983 on the history of cartography in Ireland. Dublin: Paul Ferguson, 1983. Available from Department of Geography, University College, Dublin.

Ordnance Survey of Ireland/Northern Ireland Ordnance Survey in Ireland: an illustrated record. Dublin, 1991.

See the British Library Map Library Reading List 4, on the history of cartography in Ireland, for further references.

Contact

Copyright Administration
Ordnance Survey Ireland
Phoenix Park
Dublin
8
Ireland

Tel: +44 (0)(+353-1) 820 6100
Fax: +44 (0)(+353-1) 820 4156

E-mail: custserv@osi.ie