OSNI Townlands: Historic Land Parcels of Northern Ireland

Northern Ireland's OSNI Largescale Townlands dataset contains polygon boundaries for townlands, an ancient land measurement system unique to Ireland. The data was derived from the OSNI Largescale database in 2013 and has been topologically cleansed to create a seamless spatial dataset. Townlands vary in size from a few acres upwards and are particularly important for historical and genealogical research.

Use Cases

• Genealogical research based on historical land records and place names.
• Historical mapping and analysis of land use patterns from townland boundaries.
• Integrating historical administrative boundaries with modern geospatial datasets.

Strengths

• Data is topologically cleansed, indicating a focus on geometric consistency and seamless polygon edges.
• Derived from the authoritative OSNI Largescale database, suggesting a reliable source.
• Available on multiple open data platforms, indicating established use and validation.

Limitations

• Specific column names and a precise row count are not provided in any source, limiting understanding of the data structure.
• The core data is from 2013, which may not reflect recent boundary changes.
• Conflicting license references exist between 'OGL-UK-3.0' and a URL; the exact terms require verification.

Provenance

Source

Ordnance Survey Northern Ireland (OSNI) Largescale database.

Collection Method

Derived, topologically cleansed, and attributed from the source database.

Time Range

2013

Freshness

Last updated date cited as 2026-04-15 on two platforms, but the underlying data is from 2013.

Geography

Northern Ireland