How it's made

From the 1926 census to your wall

Every Homeplace map starts with a count of real people, written down by census enumerators a century ago. Here is where the numbers come from and what we do with them.

Why 1911 for the six northern counties?
Northern Ireland took its own census in 1926, but its household forms were lost, most likely destroyed during the Second World War. The 1911 census is the latest count that survives for those six counties, so we use it there.
How is the map made?
We count every person with the surname in each of the 3,676 census districts, then divide by everyone living there. A parish where half the people share your name now outranks a city where a few thousand do. We blend each district with its neighbours, because families lived across lines on paper, and shade the result in seven bands. The four steps below show it on the Sullivan map.
Does the map show my own family?
It shows where people with your surname lived when the census counted them. It is not a family crest and makes no claim about one family's line. To mark where your own people came from, add a home place to your map.

The census

Two counts, all 32 counties

The Census of Ireland 1926 was the first full count of the new state. Its household returns opened to the public in April 2026, a hundred years on. We use it for the twenty-six counties.

For the six northern counties we use the Census of Ireland 1911. Both come from the National Archives of Ireland.

3,676census districts on every map
1926for the twenty-six counties
1911for the six northern counties

The calculation

Four steps, on the Sullivan map

The Sullivan map covered in gold dots, thickest on the Beara peninsula

STEP 1

Count every person

We count every person with the surname in each of the 3,676 census districts. The Sullivan map counts 34,660 people. Each dot here stands for ten of them, placed in their own district.

The Sullivan map with each census district shaded, darkest around Beara

STEP 2

Shade each district by its share

A raw count favours big towns, so we divide each district's Sullivans by everyone living there and shade the district by people per 1,000.

Adrigole, Co. Cork: 567 Sullivans ÷ 1,276 people × 1,000 = 444 per 1,000

A parish where nearly half the people share your name now outranks a city where a few thousand do.

The Sullivan map with fine contour bands following the district shading

STEP 3

Smooth across the borders

District borders are lines on paper; families lived across them. We blend each district's figure with its neighbours, in steps out to 10 km.

The finished Sullivan print in seven smooth bands

STEP 4

Seven bands and a key line

The finished map sets the result in seven bands. The foot of every print says what its lightest shade means for that name. On the Sullivan map: 180 or more Sullivans in every 1,000 people.

Names and spellings

Your spelling, in Irish too

Every spelling carried by 500 or more people gets its own map, so Brown and Browne each show their own ground. Under the name sits its Irish form, checked against Woulfe's Irish Names and Surnames (1923) and the Gaois database of Irish surnames.

Census of Ireland 1926 and 1911: National Archives of Ireland, CC BY 4.0. Coastline © Tailte Éireann, CC BY 4.0. District centres © OpenStreetMap contributors, ODbL.

Make your map