Labor Day is a United States federal holiday observed on the first Monday in September (September 3 in 2012) that celebrates the economic and social contributions of workers.

Recent research indicates that, in 1882, Matthew Maguire, a machinist, first proposed the holiday while serving as secretary of the CLU (Central Labor Union) of New York.^[1] Others argue that it was first proposed by Peter J. McGuire of the American Federation of Labor in May 1882,^[2] after witnessing the annual labor festival held in Toronto, Canada.^[3]