Kathryn O'Hay Granahan was born on 7 December 1894 in Easton, Pennsylvania, USA. She was married to William Thomas Granahan. She died on 10 July 1979 in Norristown, Pennsylvania, USA.
Served as chair of the House Subcommittee on Postal Operations, and worked with Postmaster General Arthur Summerfield to pass the Granahan bill that allowed for the seizure and detention of the mail of anyone suspected of trafficking in obscenity.