Labor Day is a well known tradition, every first Monday in September. Labor Day had been thought, and still is, to be created by Peter J. McGuire. Labor Day wasn't really created on a Monday or Sunday, but AFTER the first Monday, on a TUESDAY, in 1885, had it been announced in New York City that it was a holiday. Four more states, would it be created or adopted?, the Labor Day holiday. Thus, I think, making it an official holiday, unless I mistook the information, which is quite possible, being.....me.
U.S. DOL - The History of Labor Day