it is not official a holiday
On June 28, 1968
1919
The Fourth Of July
20231
because
1891
It became a holiday because of all the soldiers who gave their lives and used this day as a remembrance day (British answer).
It became a federal legal holiday in 1975
Abraham Lincoln proclaimed the day a national holiday in 1863
well apparently the government to pass a law saying it is a holiday but it is really hard to get your own holiday.
September 1979