> For the complete documentation index, see [llms.txt](https://docs.os.uk/osngd/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.os.uk/osngd/~/changes/1810/data-structure/administrative-and-statistical-units.md). # OS NGD Administrative and Statistical Units {% hint style="warning" %} ## Three new collections will be added to this theme in March 2026 Three new collections are being added to the OS NGD Administrative and Statistical Units Theme at the end of March 2026: * [OS Functional Areas](/osngd/~/changes/1810/data-structure/administrative-and-statistical-units/functional-areas.md) * [OS GB Postcodes](/osngd/~/changes/1810/data-structure/administrative-and-statistical-units/gb-postcodes.md) * [OS NI Postcodes](/osngd/~/changes/1810/data-structure/administrative-and-statistical-units/ni-postcodes.md) Data schema version 1.0 for the six new feature types ([Retail Area Aggregated](/osngd/~/changes/1810/data-structure/administrative-and-statistical-units/functional-areas/retail-area-aggregated.md), [Retail Area Major](/osngd/~/changes/1810/data-structure/administrative-and-statistical-units/functional-areas/retail-area-major.md), [Retail Area Minor](/osngd/~/changes/1810/data-structure/administrative-and-statistical-units/functional-areas/retail-area-minor.md), [Postcode Unit Area](/osngd/~/changes/1810/data-structure/administrative-and-statistical-units/gb-postcodes/postcode-unit-area.md), [Postcode Unit Point](/osngd/~/changes/1810/data-structure/administrative-and-statistical-units/gb-postcodes/postcode-unit-point.md) and [Postcode Unit Point](/osngd/~/changes/1810/data-structure/administrative-and-statistical-units/ni-postcodes/postcode-unit-point.md)) in the new collections is currently not available through the live access services. Information about the three new collections has been added to this page to give you early insight. The information is as accurate as possible, but is subject to change before launch. {% endhint %} ## Introduction to the theme Administrative and Statistical Units are the geographical extent of administrative, legislative, regulatory, electoral, statistical, governance, service delivery and activity management areas. OS NGD Administrative and Statistical Units Theme data is the most comprehensive and high-quality set of area data available for Great Britain ever produced by OS. You can use the datasets to perform quick and accurate searches as well as high-level visualisation and spatial analysis of features. The [OS Boundaries Collection](/osngd/~/changes/1810/data-structure/administrative-and-statistical-units/boundaries.md) provides a definitive dataset of administrative and electoral boundaries and their names for England, Wales and Scotland. Government Statistical Service (GSS) codes are contained within the data and are supplied by the Office for National Statistics (ONS) and the National Records of Scotland (NRS). From the end of March 2026, the theme will also include the [OS Functional Areas](/osngd/~/changes/1810/data-structure/administrative-and-statistical-units/functional-areas.md), [OS GB Postcodes](/osngd/~/changes/1810/data-structure/administrative-and-statistical-units/gb-postcodes.md) and [OS NI Postcodes](/osngd/~/changes/1810/data-structure/administrative-and-statistical-units/ni-postcodes.md) Collections. These are notional geographies which have been algorithmically derived from other OS NGD data. * The three new retail areas feature types in the OS Functional Areas Collection define the notional geographic extents of retail locations across Great Britain, identifying clusters of buildings with retail addresses. * The two postcodes collections provide complete, analytical and authoritative postcode datasets for Great Britain and Northern Ireland; they are designed to provide a detailed view of postcodes. Full UK postcode coverage is available if you combine data from the two collections as the identical schemas enable compatibility. ## Data structure The OS NGD Administrative and Statistical Units Theme is made up of four collections, which in turn are comprised of 23 feature types. The four collections are OS Boundaries, OS Functional Areas, OS GB Postcodes and OS NI Postcodes.
Tree diagram showing the data structure of the OS NGD Administrative and Statistical Units Theme. It lists the theme name, collection names, and feature type names.

OS NGD Administrative and Statistical Units Theme data structure diagram showing the theme name, collection names and feature type names.

## Unique identifiers At least one of the following four unique identifiers is provided with each feature within the OS NGD Administrative and Statistical Units Theme: * **OSID (Ordnance Survey Identifier)**: The primary identifier and unique key for this theme. * **TOID (Topographic Identifier)**: An additional secondary identifier which can aid further data linking. TOIDs are an optional attribute and therefore will not always be provided with every feature. * :new: **Feature ID**: For a small number of feature types in OS NGD where it is not possible or necessary to have identifiers that persist over time, the Feature ID is used as the primary identifier. The Postcode Unit Area, Retail Area Aggregated, Retail Area Major and Retail Area Minor Feature Types in this theme use this unique identifier. The notional extents of the retail area features and Postcode Unit Area features are regenerated periodically (for example, monthly for the latter), at which point all features will get a new Feature ID. * **GSS (Government Statistical Service) codes**: A system of referencing for administrative, electoral, and statistical geographies. {% hint style="info" %} Please note that Boundary High Water Mark, Ceremonial County, Historic County, Historic European Region, and Polling District features in the OS Boundaries Collection do not have GSS codes or TOIDs allocated to them; however, they do have OSIDs allocated to them. Polling District features have an additional unique identifier of Polling District Identifier. {% endhint %} ## Useful links * An [introductory guide to OS NGD Administrative and Statistical Units Theme data](https://docs.os.uk/more-than-maps/data-demonstrators/addressing-and-location-demonstrators/os-ngd-boundaries) is available on our [More than Maps](https://docs.os.uk/more-than-maps) site; this guide details the layers, formats and attribution available for data in the OS Boundaries Collection. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.os.uk/osngd/~/changes/1810/data-structure/administrative-and-statistical-units.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.