Works Created on or after January 1, 1978:
Creators retain rights to the work for the life of the creator plus 70 years. In the case of works for hire (created for an employer) or works anonymously created the time frame is either 95 years from publication or 120 years from creation, depending in which is shorter.
Once a work has moved out of copyright protection it is considered to be in the public domain.
Works created prior to January 1, 1978:
Works created prior to January 1, 1978 vary in term of protection depending on several factors. The best way to determine the status of a work created before January 1, 1978 is to consult chapter 3 of the U.S. Copyright Act. Due to the challenging nature of copyright law, it is never safe to assume a work is not protected by copyright unless it was published prior to 1926 (as of January 1, 2022).
Unpublished Materials
Unpublished materials, like diaries and correspondence, created prior to 1978 are protected for the life of the author plus 70 years. Unpublished material created after 1978 are protected in the same manner as published works created after 1978.
Expansion of U.S. Copyright Term
Bell, Tom W. "Trend of Maximum U.S. General Copyright Term." 2001. Licensed under CC BY-SA 3.0.