Skip to Main Content
About Us Services Research Get Help

What is Public Domain?

The Public Domain encompasses:

  • Works published in the U.S. prior to 1928;
  • Works whose copyright has expired or were not renewed;
  • Works for which the copyright owner has intentionally and explicitly "dedicated" it to the public domain;
  • Works created by U.S. Government employees during the course of their employment;
  • Works which do not qualify for copyright protections (such as ideas, common knowledge, data points etc.).

Public domain is different than "publicly accessible" or "free online." Read more about the Public Domain here.

CC0 - Creative Commons zero - donated to the public domain CC0: "No rights reserved"

CC PD. Creative Commons Public Domain mark. Identified as being in the Public Domain. CC PD: "No known copyright"

Public Domain Content

Government Publications

Most content found on .gov websites by the US Federal Government is free of any copyright restrictions and in the public domain.  However, look closely at .gov content--sometimes the materials have been contracted out or developed in partnership with a company or organization, and in these cases, a traditional all rights reserved copyright may be present.


  • A great place to start a search is
  • Try to search a specific agency's website.  A-Z List of Federal Agencies. Many times these materials are not retrieved with simple Google searches.  

Here are some examples of US Federal Databases:

  • The Homeland Security Digital Library is a collection of documents related to homeland security policy, strategy, and organizational management. Topics include maritime, unmanned aerial systems, terrorism, epidemics and many more. 


  • SciTech Connect is a collection of science, technology, and engineering research information from the U.S. Department of Energy.


Copyright by State