The 1940 United States Senate election in Pennsylvania was held on November 5, 1940. Incumbent
Democratic U.S. Senator
Joseph F. Guffey successfully sought re-election to another term, defeating the
Republican nominee, Jay Cooke.
As of 2023, this is the last time that
Mifflin County and
Montour County voted Democratic in a Senate election. This was also the last time until 1991 that Democrats won this Senate seat, and the last until
2006 that they were elected to this seat for a full term.