Northern Ireland Townland Boundaries from 2013 OSNI Data

A 2013 vector polygon dataset of townland boundaries in Northern Ireland, derived from the Ordnance Survey of Northern Ireland (OSNI) Largescale database. The dataset has been topologically cleansed to create a seamless map of these small, historically significant land divisions. It is published by OpenDataNI under the OGL-UK-3.0 license.

Use Cases

• Mapping historical land divisions based on the townland boundary polygons.
• Conducting genealogical research using the ancient land measurement system described.
• Performing spatial analysis on small administrative areas of varying size.
• Integrating historical boundary data into modern GIS applications.

Strengths

• Derived from the authoritative OSNI Largescale database.
• Data has been topologically cleansed to create a seamless dataset.
• Covers the specific and historically significant townland system of Ireland.

Limitations

• Data is from 2013 and may not reflect recent boundary changes.
• Column-level documentation is absent; field semantics must be inferred after download.
• The exact scale (e.g., row count) of the dataset is unknown.

Provenance

Source

Ordnance Survey of Northern Ireland (OSNI) Largescale database.

Collection Method

Derived, topologically cleansed, and attributed from source database.

Time Range

2013

Freshness

Last updated 2026-04-15 14:22:06.332451; freshness should be verified.

Geography

Northern Ireland