Counties and Unitary Authorities: Ultra Generalised UK Boundaries

Ordnance Survey and ONS provide digital vector boundaries for Counties and Unitary Authorities in the United Kingdom. The dataset contains ultra generalised (500m) boundaries clipped to the Mean High Water coastline. It is available via ArcGIS REST services and multiple file formats for geospatial analysis.

Use Cases

• Creating thematic maps of UK counties based on official administrative boundaries.
• Performing spatial joins to aggregate data to the county/unitary authority level.
• Analyzing regional patterns using a consistent, coastline-clipped boundary set.
• Integrating administrative geography into GIS software for planning and visualization.

Strengths

• Contains intellectual property from authoritative sources: Ordnance Survey and the Office for National Statistics.
• Boundaries are ultra generalised (500m) and clipped to the coastline, which is suitable for small-scale mapping.
• Available on multiple platforms (eu_open_data, uk_data), indicating established use and distribution.

Limitations

• Column names and exact record counts are unknown from the provided metadata.
• Sources disagree on the reference date (December 2025 vs. December 2020), creating ambiguity about the current version.
• License information is not provided in any source.

Provenance

Source

Ordnance Survey and Office for National Statistics (ONS)

Collection Method

Official digital vector boundary production.

Time Range

As at December 2025 (primary source), with a conflicting reference to December 2020.

Freshness

Last updated metadata indicates 2026-05-13, but the underlying data reference date is December 2025.

Geography

United Kingdom (Counties and Unitary Authorities)