*NEW* I’ve updated the advice I provide here about finding maps in PRONI, especially on how to find the OS 25″ County Series, in the wake of last week’s lecture.
The two best guides to using maps in local history research are:
Trevor Parkhill, ‘Ordnance Survey Maps in the Public Record Office of Northern Ireland’, Ulster Local Studies 14, no. 2 (1992), pp 72-82.
Jacinta Prunty, Maps and Map-Making in Local History (Dublin: Four Courts, 2004).
Cover of Jacinta Prunty's Maps and Map-Making in Local History (Four Courts Press, 2004)
Prunty’s book covers a whole range of different maps, not just the OS ones, and includes some really excellent appendices such as basic map scales, coversion charts and guidance on how to produce your own maps of your local area (maybe something I ought to consider!). Parkhill’s is just the clearest explanation of the OS system that I’ve come across. PRONI’s OS helpsheet provides a short overview of their collection.
If you are trying to find the OS maps for your area, the key piece of information you need to get is the sheet number(s). To take OS/1 as an example. Because the scale was so large (remember, that’s detailed), the whole island couldn’t fit onto a single page, so the maps had to be broken down into ‘sheets’. Each sheet was given a number. So, the number for Kilwaughter is 34, 35, 39 and 40, with the bulk of the parish located on sheet 40. How do I know this? Well, it can be a bit complicated. [In the old days it worked like this] Nowadays, you can simply search PRONI’s Geographical Index.
1. Go to the Geographical Index, and click on the links to take you to the parish that you are interested in. Don’t try and find your townland, because the sheet numbers are only listed next to parishes.
2. There, in the table, you will see a column for ‘OS Map Ref No’. That is the sheet number. Take a note of this.
3. PRONI has organised the numbering system for the OS maps in a highly logical way. Antrim is 1, Armagh is 2 and so forth. So, OS/1/1 is the First Edition Six Inch map for Antrim. If I add /40 to the end, I’ll get the sheet I need for Kilwaughter.
4. If you want to find subsequent editions of the 6” series, then the same sequence applies, except you add a ‘2’ or ‘3’ or ‘4’, depending on the edition you want. So, a fourth edition 6” for Kilwaughter would be OS/6/1/40/4. Whew!
Geographical Index result for Kilwaughter, with OS 6" County series sheet numbers in the far right column
You would think that finding sheet numbers would be made a lot easier now that PRONI’s catalogue is online. And to a certain extent it is. Using the ‘Browse’ function, you can search by OS number, and using the PRONI system (of ’1′ for Antrim, ’2′ for Armagh, etc) drill down to the sheet number quite easily. However, the catalogue entries for each sheet don’t tell you which townland or parish is on that sheet. If you don’t know what the sheet number is, the online catalogue will not be able to help you. Frustrating! Not only that, if you try and search, using the ‘Search’ function, for your parish name, the OS maps won’t, for the most part, appear, because there is no place name in the catalogue entry to identify them. That’s why getting the right sheet number is so important. And finding the sheet number is something you have to do before going to the catalogue. Which is why you should start your search with the Geographical Index.
25″ County Series
In the 1890s, the OS began to produce a new series of maps. These were much more detailed (remember, larger scale). The scale adopted here was 1:2500 (or 25″ to the mile), which resulted in 16 sheets being produced for every ONE of the 6″ series. The first series was produced between 1894-1904; a second series was produced between 1920-24. My original thought was that the numbering system would be entirely new for this series, and that it would start at one and work its way across, but this has proved not to be the case. Sheet numbers in this series are provided as a sub-set of the original 6″ sheet number. So, for sheet number 40, the 25″ series will number them as 40/1, 40/2, and so on. If you want to find the 25″ sheets for your area, it might be easier if we took it in steps.
1. Make sure you have the first edition 6″ series sheet numbers for your area, which you got from the Geographical Index. These form the basis of the 25″ numbering system. For Kilwaughter, these are 34, 35, 39 and 40.
2. Take one of the sheet numbers and think of the map it represents as a rectangle. Now, divide that rectangle into 16 smaller rectangles (that will be four across and four down). Starting in the top, left hand corner, give the first rectangle the number 1. Then, always moving from left to right, move across the top row and work your way down through the rows. These are the specific sheet numbers for the 25″ maps. As I said, for my sheet 40, the sixteen sheets will be a sub-set, so they will be numbered 40/1, 40/2, 40/3 and so on up to 16. The only problem is, there is no key; there is no large map of Ireland which identifies on which of these 16 sheets your area will fall. You will have to take a guess, or call up all of the maps that look close to your area, and take your chances. This could be a bit hit or miss, but that’s the way it works.
3. Once you have your approximate sheet numbers, the rest is easy. The general reference number for the 25″ series is OS/10. And, the county numbers (1 for Antrim, 2 for Armagh, 3 for Down, etc) also stay the same. So, to find Drumnahoe townland on the 25″ series, I have identified sheet 7 as one of the most likely. Put the whole reference together gets me OS/10/1/40/7, and that’s the number I put into the ‘order document’ box in the Search Room.
4. To find the second series, I’ll bet my granny’s best Sunday hat that you put a /2 at the end (but I have to confirm that).
If this makes you despair of ever finding a map, always remember that there PRONI staff in the Search Room who know all about this, and will be more than willing to help you find what you are looking for.
Town Maps and Plans
Something I haven’t said anything about is town maps. Parkhill is great on this. He explains quite clearly about OS/8 and OS/9, and how some towns were mapped on a very large (remember, that means detailed) scale, and others on the standard 6″ scale. He also points out the difference between published maps and manuscript maps (not published). When it comes to finding town maps, the PRONI catalogue is more helpful.
1. Use the ‘Browse’ function, search for ‘OS’. This will bring up the whole OS series, and you can see at a glance what each number refers to.
2. Click on ‘OS/8’ or ‘OS/9’ and drill down to see if you can find your town. It will mean browsing through several pages of entries, but this can really pay off. The alphabetical system seems to repeat itself a few times, so do persevere to the end. Not only that, but think about the concept of ‘town’ quite broadly. When I was looking for ‘Larne’ I came across ‘Ballynure’, which I wasn’t expecting to find, mainly because today, it doesn’t really come across as a town, but more as a village. So just be aware of other urban settlements near to the one you’re interested in, and you might get lucky. And finally, when you do find an entry for your town, be sure to drill down to the very last link, until you can’t go any farther. I discovered quite a number of these links opened up to reveal two or three separate maps under the one listing. So, for example, OS/9/7 is the reference for a manuscript map of Larne. However when I opened it up, I got three maps in total: /1, drafted in 1833, /2, from 1893-4 and /3, a ‘composite index map’ of /2, created in 1896. I’d not have expected to find a map of the 1830s stuffed in here, so that was a nice little find.