The "public domain" refers to creative works that are not protected by copyright, meaning anyone can use them freely without permission from the original creator because they belong to the public at large; this typically happens when a copyright has expired or if the work was never eligible for copyright protection in the first place.
There are five common ways that works arrive in the Public Domain.
1. The Copyright has expired
For works first published in the United States prior to 1978 copyright expires 95 years after publication. Today (01-21-2025) works published in 1929 have entered the public domain in the United States. For works published after 1977, copyright lasts for the life of the author(s) plus 70 years. The earliest a work published after 1977 will enter the public domain is January 1 2049.
2. The copyright owner failed to comply with the required formalities.
Works first published (or within 30 days of foreign publication) in the United States before 1978 immediately entered the public domain if they were generally published without a proper copyright notice. Which required the copyright symbol © (for phonorecords, the symbol ℗) word copyright of the abbreviation copr. along with the name of the holder and the date of first publication. © 1959 John Doe.
Works published between 1978 and 1989 without a proper copyright notice would enter the public domain unless registration as made within 5 years of initial publication with the Copyright Office and reasonable effort was made to correct the omission on all copies distributed in the U.S. after the omission is discovered.
One of the most famous works to enter the Public Domain for failure to follow the required formalities is Night of the Living Dead.
3. The copyright owner failed to renew the copyright.
Works published in the United States before 1964 fall into the public domain if copyright was not renewed with the Copyright Office during the 28th year after publication.
For works published between 1920 and 1963, research with the Copyright Office is needed to know whether the item is in the Public Domain. For a helpful guide to researching Copyright Office records, please see this guide from Stanford University Libraries.
4. The copyright owner deliberately places the item in the Public Domain
Sometimes, a copyright owner will choose to release their work to the Public Domain. They can do this via a CC-0 license or by placing a statement such as "This work is dedicated to the Public Domain" on their work.
5. Copyright law does not protect this kind of work.
As a matter of law Copyright in the United States does not adhere to "a work prepared by an officer or employee of the United States Government as part of that person's official duties". With the exception of works prepared by civilian employees of institutions such as West Point and Annapolis, known as "covered institutions."
Copyright law also does not protect the titles of books or movies, nor does it protect short phrases such as, “Beam me up.” Copyright protection also doesn’t cover facts, ideas, or theories, which has important ramifications for the collection of data.
