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Green Island Crannog is an early Christian artificial island settlement located in Derry, Northern Ireland. Crannogs were dwelling platforms constructed in lakes and wetlands, typically consisting of timber structures built upon foundations of timber posts, stones and organic material. This example sits upon bedrock of the Southern Highland Group, a sequence of psammite and pelite laid down during the Middle Cambrian period, now buried beneath later deposits that form the surrounding landscape.
The crannog occupies a strategic position within the waterlogged terrain of the region, where the underlying geology provided both stability and access to water resources essential for early Christian communities. The construction technique—raising domestic structures above water level—offered protection and facilitated fishing and aquatic transport, making such settlements ideal for settlements during the early Christian period in Ireland.
Green Island Crannog is recorded on the Historic Environment Division's register under reference 11852, recognising its archaeological significance as evidence of early Christian settlement patterns and construction methods in Ulster. The site contributes to understanding how communities adapted to and exploited the distinctive wetland environments of northern Ireland during this formative period of Irish history.
Green island. crannog is a scheduled monument protected by Department for Communities NI under reference 11852. View the official record →
Green Island Crannog is an early Christian artificial island settlement located in Derry, Northern Ireland. It is designated a Scheduled Ancient Monument by DfC Northern Ireland (NISMR) under reference 11852.
Green island. crannog dates from the e.christ. period, and is classified as a crannog. It is one of over 32,000 scheduled monuments protected across the UK.
Green island. crannog is a Scheduled Ancient Monument, legally protected by DfC Northern Ireland (NISMR) — the body responsible for designating and safeguarding heritage sites in Ni. The official designation reference is 11852.
Several scheduled monuments lie within 10 km, including Castle of anagh. tower-house (0 km), St. columb's stone. inauguration stone (3.5 km), Rath (motte & bailey?) (3.5 km).
This page is just one thread. A full Aubrey report pulls together 14 strands of Green island. crannog's history, each drawn from the record and mapped to the exact spot:
Every location is different. Not every section appears for every place, only what the historical record actually holds turns up in a report.
Green island. crannog stands on Southern Highland Group, bedrock that formed in the Middle Cambrian. The rock here is psammite and pelite.