The first Labor Day in the United States was celebrated on September 5, 1882 in New York City. In the aftermath of the deaths of a number of workers at the hands of the U.S. military and U.S. Marshals during the 1894 Pullman Strike, President Grover Cleveland put reconciliation with Labor as a top political priority. Fearing further conflict, legislation making Labor Day a national holiday was rushed through Congress unanimously and signed into law a mere six days after the end of the strike. All 50 U.S. states have made Labor Day a state holiday.
(From Wikipedia - The Free Encyclopedia)