Overview[]
Under the 1909 Copyright Act, federal copyright was secured on the date a work was published or, for unpublished works, on the date of registration. A copyright lasted for a first term of 28 years from the date it was secured. The copyright was eligible for renewal during the final (28th year), of the first term. If renewed, the copyright was extended for a second (renewal term) of 28 years. If it was not renewed, the copyright expired at the end of the first 28-year term, and the work is no longer protected by copyright.
Source[]
U.S. Copyright Office, "Duration of Copyright" (Cir. 15A) (Aug. 2011) (full-text).