Holidays and anniversaries can often sneak up on people. That seems to be the case in Philadelphia on the first anniversary of the Declaration of Independence: July 4, 1777.
In the defense of the Continental Congress, they were a bit busy. In that first year of independence, they had made what would be the first of several evacuations, meeting in Baltimore for several months while the British occupied Philadelphia. During their time in Baltimore, the Congress had commissioned the first printing of the Declaration of Independence to include the names of (nearly) all the signers.