THE FLAG DAY IS CELEBRATED IN JUNE14 COMMEMORATING ADOPTION FLAG OF UNITED STATES IN 1777 BY RESOLUTION OF SECOND CONTINENTAL CONGRESS. IN JUNE 14 UNITED STATES CELEBRATES ALSO THE HAPPY BIRTHDAY OF UNITED STATES ARMY. IN 1916 PRESIDENT THOMAS W. WILSON ESTABLISHED OFFICIALLY 14 JUNE AS FLAG DAY.. ACCORDING ACT CONGRESS 3 AUGUST 1949 THE NATIONAL FLAG DAY IS NOT A FEDERAL HOLIDAY..