Distribution Of Prehistoric Forts in Ireland

Map created by Daniel Kirkpatrick aka reddit user SarquinThe map above shows the distribution of different types of prehistoric forts in Ireland. From the map author:

Here are all recorded prehistoric fort locations across Ireland.

The map is populated with a combination of National Monument Service data (Republic of Ireland) and Department for Communities data for Northern Ireland.

The map was built using some PowerQuery transformations and then designed in QGIS. Note the data isn’t an exact match between the datasets as Northern Ireland doesn’t have all the categories provided for the Republic.

I previously mapped hillforts using the Atlas of Hillforts data. Several commented about gaps. This was largely due to the way the data is categorised, with Raths and Ringforts far surpassing hillforts.

For those who want to see the data sources check out NMS here https://www.archaeology.ie/collections-and-publications/publications/monument-class-and-scope-notes/ and the UK Open Data here https://www.data.gov.uk/dataset/46240fa5-db15-469e-b1c8-0460504b951c/northern-ireland-sites-and-monuments-record For the tooling, I used QGIS and PowerQuery (Excel).

If interested in more background, I have summarised my research on Irish hillforts here: https://www.danielkirkpatrick.co.uk/historical-sites/irish-hillforts/

Here are the total number of each:

Rath: 28,065
Ringfort – Cashel: 3,518
Ringfort -Unclassified: 1,817
Promontory Fort: 578
Hillfort: 206

And here’s a little bit more about each one:

Rath (plural: Ratha / Raths)

Definition: An earthen ringfort, essentially a circular enclosure with one or more banks (ramparts) and ditches (fosses).
Material: Built mostly of earth.
Dating: Mostly Early Medieval (c. 500-1100 CE).
Function: Farmstead enclosures, they were domestic settlements, not military fortresses. A rath usually enclosed wooden houses, animal pens, and storage areas.
Scale: Extremely common, your number (28,065) comes from the number recorded in Irish surveys, making them one of the most widespread archaeological monument types in Europe.

Ringfort (Cashel)

Definition: A stone-built version of a rath.
Material: Instead of earthen banks, they are made of stone walls (often dry-stone).
Dating: Same period as raths (Early Medieval).
Function: Domestic settlement enclosure, but in areas without much soil (like the Burren in Co. Clare or western Ireland), stone was the easier material.
Note: “Ringfort” is a generic term for both raths (earthen) and cashels (stone), but archaeologists distinguish them by material.

Promontory Fort

Definition: A defended headland or coastal site, using steep cliffs and sea on most sides, with one or more man-made ramparts cutting off the landward approach.
Material: Earth and stone ramparts, but relying heavily on natural topography.
Dating: Appear in the Late Bronze Age and Iron Age (c. 1000 BCE – 500 CE). Some reused later.
Function: Likely had mixed roles:
- Strategic/military defense.
- Ritual or elite status sites (some have evidence of feasting and high-status metalwork).
- Possibly linked to control of maritime trade routes.

Hillfort

Definition: Large enclosures built on hilltops, with multiple concentric banks and ditches.
Material: Earth and timber ramparts (occasionally with stone elements).
Dating: Mainly Late Bronze Age – Iron Age (c. 1200 BCE – 500 CE).
Function: More than just defensive; often seen as centers of power, assembly, ritual, and refuge.
Scale: Much larger than raths or cashels. Famous examples: Hill of Tara, Dún Ailinne, Navan Fort (Eamhain Mhacha).