Clonbrin Causey (Edercloon) – Longford/Offaly Bog Road
Clonbrin Togher · Edercloon Trackways
Late Iron Age (La Tène)·Irish Iron Age (Ulster–Connacht)·🇮🇪 Connacht/Leinster, County Roscommon–Longford, Edercloon bog, Ireland
About
About Clonbrin Causey (Edercloon) – Longford/Offaly Bog Road
The Edercloon cluster of Iron Age oak plank roads, of which Clonbrin Causey (Togher EDC-1) is the flagship: a 1.5-km oak plank road (120 BCE dendro) 3.5 m wide with transverse ash sleepers and marginal drainage ditches, linking the drumlin edge to a wetland island. Excavated 2006–2009 during N4 bypass, Edercloon produced six superimposed trackways showing 400-year bog road evolution; Clonbrin Causey featured heavy longitudinal oaks pegged to ash runners, bearing loaded cart wheel ruts (1.4 m gauge) indicating Iron Age wheeled transport. Preservation in raised bog is exceptional; the causey is conserved in Corlea Heritage Centre.
Why it mattersOnly Iron Age bog road with preserved wheel ruts proving wheeled transport in Ireland.
Open questions
Mysteries & theories
Mysteries
- 01Cart gauge standardization
Theories
- 01Island sanctuary access
Theories are interpretations, not findings. The seal above tells you how much scholarly weight the place carries.
History
How it came to be
- Built
- c.120 BCE (dendro) to 100 CE
- Period
- Late Iron Age (La Tène)
- Culture
- Irish Iron Age (Ulster–Connacht)
- Builders
- Connacht bog road builders
- Purpose
- Wheeled causeway across raised bog to island settlement
- Abandoned
- c.200 CE raised bog growth
- Rediscovered
- 2006 N4 Dromod–Roosky bypass excavation
- Excavation
- Excavated
120 BCE
Clonbrin Causey oak felling (dendro)
2006
Excavation ahead of N4 bypass
On the ground
Structures & features
53.6600° N · 7.8800° W · 45 m · 2 mapped features
Clonbrin Causey Main Plank Road
earthwork1.5-km oak plank causeway 3.5 m wide with cart ruts
53.6610° N · 7.8810° WEdercloon Underlying Brushwood 2
earthworkEarlier 400 BCE brushwood trackway beneath causey
53.6590° N · 7.8780° W