The first Labor Day observance happened on September 5, 1882, on a Tuesday
at that time, when thousands of workers of the Central Labor Union of New York
marched from Fifth Avenue to Union Square (above), where picnics, fireworks,
and rallies were held, all in support of an 8-hour workday.

It became a national holiday in 1894, following the deaths of a number of striking
Railway Union workers as they were confronted by troops of the Illinois National
Guard during the Pullman Strike. After reaching an agreement with the labor
movement, President Grover Cleveland rushed legislation through Congress
designating the first Monday of September as “National Labor Day”. This was
six days after the end of the strike.

Striking  Railway Union members confront National Guard troops in Chicago
during the Pullman Strike