UCC logo

How to find our ancestors using online maps

Adult Continuing Education Irish Genealogy Summer School 2016 - Ancestral Connections: Roots to the Rising

12:00 noon Tuesday 28 June 2016

G05 Western Gateway Building

by Dr Paddy Waldron

WWW version:



The Ordnance Survey Office was established in 1824.
The original survey of the entire island of Ireland at a scale of 6 inches to 1 mile was completed 22 years later, in 1846.
Ireland became the first country in the world to be entirely mapped at such a detailed scale.
More details can be found on the OSi website and a full history in JH Andrews' A Paper Landscape, repr. Four Courts Press, 2006.
Since about 2010, the OSi's historic maps of Ireland have been available online at maps.osi.ie.
More recently, additional layers have been added at geohive.ie.
There is an open source competitor at OpenStreetMap.org.

John Grenham has written ('Glory be to the Ordnance Survey', Irish Times, 8 June 2015) about what happened when "the Ordnance Survey Ireland maps website (maps.osi.ie) was taken offline and the worldwide Fraternity of Historic Map Nuts held its breath."

The official boundaries and spellings of townlands have largely remained fixed since the survey of 1824-46, with one or two minor exceptions, e.g. Ballybrown and Moyarta.

In the past and/or in some browsers, Google Maps had strange polygons in place of the true townland boundaries.

As (a) spellings of personal names in official records are far more fluid than spellings of townland names in official records and (b) there may be more than one person with the same name living in nearby townlands, it is advisable to find the townland first and then look for the person.

Taken almost two centuries earlier, in 1656-1658, the Down Survey of Ireland was the first ever detailed land survey on a national scale anywhere in the world, e.g Barony of Moyfarto (now spelled Moyarta).
(Note that Moyarta East and Moyarta West are two townlands in the Barony of Moyarta. Moyarta East and Moveen West were separated in the Down Survey by the Lisheen River; the part of the 17th century Moyarta East adjoining the Lisheen River is now the separate townland of  Breaghva.)
The 17th century Down Survey maps, 19th century Ordnance Survey maps and 21st century Google maps have been overlaid on each other, e.g. Kilkee.

The Tithe Applotment Books generally pre-date the Ordnance Survey, so that they often use non-standardised townland boundaries and spellings.
There are no matching maps and poor handwriting has also resulted in many transcription errors.
For example, Moyarta East appears to still include Breaghva and there are further differences between the transcriptions by the National Archives and by Clare County Library.

The good news is that finding your ancestral home on maps becomes much easier from 1846 on.

A Step-by-Step Approach

  1. For rural locations, identify the relevant townland:
  2. For urban locations, identify the street address(es) and precise location:
  3. Check the townland index for:
    (particularly when there are multiple townlands with the same name).
  4. Check the 1901 census or 1911 census for:
    In 1911, the rural part of Gillabbey was in Bishopstown DED.  Minerva Terrace, Gillabbey Street and Gillabbey Terrace were in Cork No. 5 Urban DED.
  5. Check the logainm.ie maps for:
    Bishopstown DED is in Cork Rural Dispensary District.
  6. In a new browser tab or window, locate the townland at maps.osi.ie:
  7. In a second browser tab (or window), locate the townland at askaboutireland.ie:
  8. In a third browser tab, locate the townland at maps.google.com:
There are similar websites for other parts of the world, e.g. Philadelphia.