Copyright and License

OpenHistoricalMap (OHM) provides historical mapping and related data, licensed by contributors at the object level. Contributors are strongly encouraged to contribute data using the CC0 license, but in the interest of protecting the rights of historical data creators, such as academics, other open licenses, such as any combination of CC, BY, SA, and NC are supported, as well. You are responsible for understanding the terms of the licenses included in the data you copy, distribute, transmit, and adapt.

You are free to copy, distribute, transmit, and adapt our data, as long as you abide by the terms of the data you are copying, distributing, or adapting. If you alter or build upon the data on this site, you may distribute the result only under the terms of the underlying data objects’ licenses.

The cartography in our map tiles is licensed under the terms of the objects the tiles contain. Our map styles and documentation are licensed under the Creative Commons Attribution “No Rights Reserved” Public Domain license (CC0).

How to credit OpenHistoricalMap

We do not require any OHM-specific credit separate from those required by the underlying data. Citations, however, are appreciated as "OpenHistoricalMap contributors"

For a browsable electronic map, OHM prefers the optional credits appear in the lower-right corner of the map. For example:

Example of how to attribute OpenHistoricalMap on a webpage

Finding out more

Read more about using our data, and how to credit us, at the OHM Licence page.

Our contributors

Our contributors are many, many individuals and organizations. We would not exist without their efforts.

For further details of these, and other sources that have been used to help improve OpenHistoricalMap, please see the Contributors page on the OpenHistoricalMap Wiki.

Inclusion of data in OpenHistoricalMap does not imply that the original data provider endorses OpenHistoriicalMap, provides any warranty, or accepts any liability.

Copyright infringement

OHM contributors are reminded never to add data from any copyrighted sources (e.g. Google Maps or printed maps) without explicit permission from the copyright holders.

If you believe that copyrighted material has been inappropriately added to the OpenHistoricalMap database or this site, please send email to with "TAKEDOWN REQUEST" in the subject line.


If you have questions about your use of the OpenHistoricalMap name, please see our Trademark Policy.