Get an ISIL for your library

Street sign for a library

An ISIL identifies a library or related organisation. It's used to identify the originator or holder of library and archive collection material. If your organisation is in the UK, you can request an ISIL from the British Library.

How to obtain an ISIL

Requests for an ISIL for one organisation will be processed within three days. 

You can request codes for more than one organisation or for multiple sub-units of one organisation. This processing will take longer depending on the overall number and will be assessed on a case-by-case basis. Please contact us to discuss.

We fulfil requests as promptly as possible. Please help us by requesting your ISIL in good time.

Our data is distributed under a Creative Commons CC0 1.0 Universal Public Domain Dedication licence. See more about our terms and conditions.

What is the ISIL?

The ISIL is the International Standard Identifier (ISO 15511:2011) that can be assigned to a library or related organization. An ISIL can also be assigned to sub-units of an organization.

ISILs are 16-character variable length codes which uniquely identify libraries and related organisations in an international context. They can accommodate existing national library identification systems.

The British Library is the UK National Agency for the assignment of the ISIL to organisations in the United Kingdom, Crown Dependencies and Overseas Territories. It is not responsible for the assignment of ISILs to libraries and related organisations in the Republic of Ireland.

ISILs assigned to libraries by the British Library are based on MARC Organization Codes. They are made globally unique by the addition of a country code prefix (ISO 3166-1).

The Danish Agency for Culture and Palaces is the International Authority for the registration and maintenance of the standard. Its role is to maintain a source of information about the National Agencies involved and to supervise the use of country and non-country prefixes. It also has a promotional role. 

More details about the ISIL are available from the ISIL Registration Authority.

Further information

The British Library
Collection Metadata
Boston Spa, Wetherby
West Yorkshire
LS23 7BQ
United Kingdom

Tel: + 44 (0) 1937 546124
Fax: + 44 (0) 1937 546586