In the public domain as original works of the United States federal government and/or military
This battle map image could be re-created using vector graphics as an SVG file. This has several advantages; see Commons:Media for cleanup for more information. If an SVG form of this image is available, please upload it and afterwards replace this template with {{vector version available|new image name}}.
It is recommended to name the SVG file “Battle of Marathon Greek Double Envelopment.svg”—then the template Vector version available (or Vva) does not need the new image name parameter.
Dozvoljava se umnožavanje, dijeljenje i/ili mijenjanje ovog dokumenta pod uvjetima GNU-ove licence za slobodnu dokumentaciju, inačica 1.2 ili kasnija ako ju je objavio Free Software Foundation; bez nepromjenjivih ili obveznih dijelova i bez teksta na naslovnoj i/ili posljednjoj stranici. Kopija licencije je uključena u odjeljak naslovljen GNU-ove licence za slobodnu dokumentaciju.http://www.gnu.org/copyleft/fdl.htmlGFDLGNU Free Documentation Licensetruetrue
Quoted directly from an email querying copyright status of the map: "You are welcome to use the maps stated below for the purposes outlined in your document license. We do request the following credit line, “Maps Courtesy of the Department of History, United States Military Academy.”"
Their cartographer did not actually specify the exact license of the images they have produced, so I am assuming the strictest tag.