Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (70 years p.m.a.), Mainland China (50 years p.m.a., not Hong Kong or Macao), Germany (70 years p.m.a.), Mexico (100 years p.m.a.), Switzerland (70 years p.m.a.), and other countries with individual treaties.
Uploaded a work by unknown, State of North Carolina from https://archive.org/details/northcarolinaman1961nort/page/401 North Carolina Manual. Raleigh: North Carolina Secretary of State. 1961. p. 401 with UploadWizard