This image is believed to be in the Public Domain for the following reasons. It is an unpublished archival historic photograph, of unknown authorship created more than 25 years ago, without copyright information. It is provided by American Memory which attempts to provide copyright information where available, although does not guaranty its accuracy "despite extensive research", and that unpublished work "has been dedicated to the public".
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 (50 p.m.a.), Mainland China (50 p.m.a., not Hong Kong or Macao), Germany (70 p.m.a.), Mexico (100 p.m.a.), Switzerland (70 p.m.a.), and other countries with individual treaties.