In the United States, works published before 1930 are all in the public domain under the provisions of the Copyright Act of 1909 and previous law.
[1] Works published before 1964 in the US are all in the public domain, excepting only those for which a renewal was registered with the US Copyright Office.
This law removed the requirement that a second term of copyright protection is contingent on a renewal registration.
For listings of renewals and non-renewals of periodicals and newspapers after 1923, see the complete report prepared by the University of Pennsylvania Library.
This was changed by the Copyright Act 1842, which provided for a single life-plus-seven-years term, or a 42-year one, whichever was longer.