🆕OS NGD Postcodes

The GB and NI Postcodes Collections were added to the OS NGD Administrative and Statistical Units Theme in March 2026. The collections are a replacement for the Code-Point and Code-Point with Polygons products within the OS NGD.

Example image showing Postcode Unit Area and Postcode Unit Point features over part of Exeter.

Postcode geometries are more representative of real-world features and are more intuitive to customer expectations as they more closely align with how they imagine postcodes to look. The collections enable access to all postcodes in Royal Mail's Postcode Address File (PAF). Full UK postcode coverage is available if you combine data from the two collections as the identical schemas enable compatibility.

The attribution across the three new feature types includes enhanced area, district and sector attribution; delivery point counts per postcode and postcode part (for use with PAF data), and postcode metadata. Details on how attribution is processed, integrated and applied can be found on the OS NGD Documentation site.

Feature types

• Postcode Unit Area: An area representing the notional extents of areas across Great Britain (GB) containing addresses that share a common postcode unit.

• Postcode Unit Point: Point representation of postcodes across GB, snapped to the coordinate of an address with that postcode wherever possible.

• Postcode Unit Point: Point representation of postcodes in Northern Ireland (NI), as supplied by Ordnance Survey of Northern Ireland (OSNI) via Gridlink.

Key features

• Aligned to real-world buildings, rather than abstract centres of volume.

• Consistent GB and NI schema, enabling seamless cross-border analysis.

• Postcode Unit Areas and Points, supporting both spatial aggregation and point-based workflows.

• Enhanced attribution, including postcode hierarchies and delivery point counts.

• API delivery via OS NGD (through OS NGD API – Features) for the two feature types for GB, enabling automated access and integration for the first time.

• Full national coverage with no gaps, and consistent behaviour across urban and rural contexts.

• Designed for analytics and decision-making, not just reference lookups.

Difference between OS NGD Postcodes and Code-Point with Polygons

In Code-Point with Polygons, data was derived by taking the coordinates of all addresses sharing a postcode, drawing a shape around those points and then mathematically expanding all postcode shapes so they touched with no gaps. This approach could result in multiple postcodes overlapping the same building. This meant a single building could be mistakenly perceived as having several postcodes.

The OS NGD approach reverses this logic by starting with the real world. Rather than using just the address points, we now use the whole building that point is in; only then are the shapes expanded to ensure full national coverage with no gaps. The key benefit to customers when using Postcode Unit Area data is that there is no ambiguity.

Example image showing changes made to polygons in the OS NGD to avoid cutting through Building features.

Vertical streets, where multiple postcodes previously existed at the same 2D location, are a separate file in Code-Point with Polygons. Instead, in the OS NGD, multiple features in Postcode Unit Areas can share a geometry.

Example image showing changes made to remove vertical streets in favour of stacked polygons in the OS NGD.

Benefits

The GB and NI Postcodes Collections deliver a consistent, authoritative view of postcode geography across Great Britain and Northern Ireland. They meet a critical need for reliable postcode data that aligns to real-world features and addresses rather than abstract centres of volume. The Postcode Unit Point and Postcode Unit Area Feature Types enable customers to analyse, aggregate and apply postcode-based geography with confidence at local, regional and national scales.

Ultimately, postcodes data can empower organisations to plan with confidence, improve analytical accuracy and act on trusted spatial context. By replacing legacy postcode representations with building-aligned geometries, delivered through our API (for the GB feature types), postcodes data become an essential foundation for anyone who needs to understand, analyse and ask a question based on the spatial context of a postcode.

FAQs

Frequently asked questions (and answers) on OS NGD Postcodes can be found under the OS NGD Administrative and Statistical Units Theme FAQs on the OS NGD Documentation site.