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Rough Island, O'Cahan's Garden is a prehistoric crannog situated in Derry, Northern Ireland. Crannogs were artificial or semi-artificial islands constructed in water to provide defended settlements during the Neolithic and Bronze Age periods. This particular site shows evidence of occupation spanning both these prehistoric eras, with artefacts and structural remains indicating sustained use across a considerable timespan. The crannog's location in the local waterway would have offered strategic advantages for early communities, combining access to water resources with natural protection from the surrounding landscape.
The island rests upon bedrock of the Southern Highland Group, comprising psammite and pelite formations created during the Middle Cambrian period, which shaped the underlying geology of this region. This ancient foundation lies buried beneath later deposits that accumulated during the site's occupation phases. The distinctive local geology and hydrology created suitable conditions for crannog construction, allowing prehistoric communities to establish their settlement in this particular location.
Rough Island, O'Cahan's Garden is protected as a scheduled monument by the Historic Environment Division under reference 11853, recognising its importance as evidence of early settlement patterns and construction practices in prehistoric Northern Ireland. The site contributes significantly to understanding how Neolithic and Bronze Age communities utilised the landscape and water resources of the region.
Rough island, o'cahan's garden. neolithic & bronze age occupation site & crannog is a scheduled monument protected by Department for Communities NI under reference 11853. View the official record →
Rough Island, O'Cahan's Garden is a prehistoric crannog situated in Derry, Northern Ireland. It is designated a Scheduled Ancient Monument by DfC Northern Ireland (NISMR) under reference 11853.
Rough island, o'cahan's garden. neolithic & bronze age occupation site & crannog dates from the prehistoric period, and is classified as a crannog. It is one of over 32,000 scheduled monuments protected across the UK.
Rough island, o'cahan's garden. neolithic & bronze age occupation site & 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 11853.
Several scheduled monuments lie within 10 km, including Castle of anagh. tower-house (0.2 km), St. columb's stone. inauguration stone (3.3 km), St brecan's chapel, st columb's chapel, domnach min-cluane. chapel & graveyard on earlier site (3.6 km).
This page is just one thread. A full Aubrey report pulls together 14 strands of Rough island, o'cahan's garden. neolithic & bronze age occupation site & 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.
Rough island, o'cahan's garden. neolithic & bronze age occupation site & crannog stands on Southern Highland Group, bedrock that formed in the Middle Cambrian. The rock here is psammite and pelite.