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:

Finding out more

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

Our contributors

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

• Contains data from various Natural Earth Data datasets.
• Contains data from the Newberry Library's Atlas of Historical County Boundaries.
• Contains data created by The Cambridge Group for the History of Population and Social Structures ANR Communes project.

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

Inclusion of data in OpenHistoricalMap does not imply that the original data provider endorses OpenHistoricalMap, 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.

Trademarks

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