Documents in the United States National Archives will generally not be protected by copyright because the Copyright Act says works produced by federal employees are ineligible for copyright protection. However, the National Archives, particularly its system of presidential libraries, does hold private papers donated to the government which may have copyright restrictions. The Richard Nixon Presidential Library and Museum, part of the National Archives, gives this statement on copyright in its holdings:
The Nixon Presidential Library and Museum and the National Archives and Records Administration exercise no intellectual property claims on the materials in its holdings and therefore cannot grant exclusive or non-exclusive publication privileges or usage rights for the use of materials in its holdings. Since the U.S. Government exercises no such claims on materials created by or for its offices (17 U.S.C. 105), the original work products of Federal Government organizations and its employees or agents have no known copyright restrictions.
In addition to U.S. Government works, the Nixon Presidential Library and Museum also has material in its holdings not created by the federal government which may be subject to copyright, donor, or other forms of restrictions. The National Archives does not confirm or guarantee the rights status of media records but will provide any information filed with or accompanying the material. It is the user’s responsibility to verify and secure copyright or other underlying rights status permissions before making commercial, broadcast, or other use of items in our holdings.
Records of state and local governments are eligible for copyright but some states such as Florida have waived any copyright in their public records. In Britain, documents held in its National Archives are subject to Crown Copyright but it readily licenses documents under the U.K. Open Government License, similar to the Creative Commons licenses. The U.K. National Archives discusses copyright in its holdings in this PDF.