# OS Open USRN Overview

OS Open USRN is an open dataset of all Unique Street Reference Numbers (USRNs) within [OS MasterMap Highways Network](https://docs.os.uk/os-downloads/products/transport-network-portfolio/os-mastermap-highways-network-fundamentals), with an associated simplified line geometry representing the geographic extent of each USRN.

{% hint style="info" %}
A USRN is a unique and persistent identifier for a street contained in either the National or Scottish Street Gazetteer. Every street, road, track, path, cycle track or way is assigned a USRN by a Roads Authority, Local Highway Authority or Highways England.
{% endhint %}

This product has been designed to enable users to easily share information held against a USRN with a location and to link together information associated with USRNs, enabling location-specific visualisation and analysis.

Local authorities have a statutory responsibility that means they are the source of information for both street naming and managing the highways / roads network. Each authority is provided with a USRN range that is centrally allocated and managed by GeoPlace in England and Wales, and by the Improvement Service in Scotland.

<figure><img src="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2FEAp71s5LDyJrli9Pa4pw%2Fopen-usrn-datahub-3-large.png?alt=media&#x26;token=2f48bdf6-a2a1-4eaf-a0a8-a9aae9839413" alt="Visualisation of street data on a map showing streets throughout a large urban area."><figcaption><p>A representation of OS Open USRN data against a background map.</p></figcaption></figure>

## Key features <a href="#bookmark16" id="bookmark16"></a>

The key features of the OS Open USRN product are:

* Inclusion of all live USRNs published within the OS MasterMap Highways Network, including Type 1, 2, 3 and 4 streets.
* A simplified line geometry representing the geographic extent of each street, with a single line feature for each USRN.
* Attribution that includes the USRN identifier and [Street Type](https://docs.os.uk/os-downloads/products/transport-network-portfolio/os-open-usrn/os-open-usrn-technical-specification/street-type).

{% hint style="info" %}
Information about the structure of the product can be found in the [OS Open USRN Technical Specification](https://docs.os.uk/os-downloads/products/transport-network-portfolio/os-open-usrn/os-open-usrn-technical-specification).
{% endhint %}

## Product applications <a href="#bookmark15" id="bookmark15"></a>

OS Open USRN enables users to:

* Share information held against a USRN with a location.
* Link together information associated with USRNs.
* Conduct location-specific visualisation and analysis.

This product has not been designed to be used for the street or road works statutory processes where the necessary additional detail for coordination is found in either the National Street Gazetteer (NSG) for England and Wales or the Street Gazetteer for Scotland. Nor does the product provide a topologically structured network suitable for road routing, where the additional detail and complexity provided in [OS MasterMap Highways Network](https://docs.os.uk/os-downloads/products/transport-network-portfolio/os-mastermap-highways-network-fundamentals) is required.

## Index

This overview includes the following sections:

* [What is an identifier?](https://docs.os.uk/os-downloads/products/transport-network-portfolio/os-open-usrn/os-open-usrn-overview/what-is-an-identifier)
* [Product supply](https://docs.os.uk/os-downloads/products/transport-network-portfolio/os-open-usrn/os-open-usrn-overview/product-supply)
* [Coordinate reference system](https://docs.os.uk/os-downloads/products/transport-network-portfolio/os-open-usrn/os-open-usrn-overview/coordinate-reference-system)