The United Kingdom Hydrographic Office

Admiralty paper charts are available in sets of charts grouped together as geographic folios. We’ve divided the world into 100 areas containing all of the charts of that region. The exact number of charts in any given folio varies according to what chart coverage we have published.

We’ve structured the folios to meet the needs of our defence customers, who navigate and operate mainly within regions rather than by specific trading routes. The charts are not classified and can also be used by commercial shipping.

This image shows the parameters of the folios.

Download image as a PDF

Each folio comes in a buckram folder with a folio list and correction sheet for the charts included. The list of charts that make up each folio can change weekly with the publication and withdrawal of Admiralty charts. Details of additions and changes to the folio references are detailed in the ‘Now Published and Available’ list in Section 1 of the Admiralty Weekly Notices to Mariners.

Admiralty publication NP133B contains a quick charts-to-folio reference. You should also keep this publication up to date with any changes to chart or folio references.