During World War II, there was a convalescent annex to the U.S. Naval Hospital in Swarthmore, Pennsylvania. Injured sailors would recuperate here, like Jack Kairis, the sender of this card. The view on the card isn’t so great, you can’t really tell what the building looks like since it’s covered by trees. The U.S. Naval Hospital in Philadelphia is pictured below.
Photo from The Living New Deal
Newspapers.com has a section from the Alton Evening Telegraph, an Illinois newspaper, about a sailor who was returning home after being in the Swarthmore annex from October 1944 to July 1945. He was in Normany and “his ship was sunk in the Southern France campaign.”