Annual holiday devoted to the recognition of working people's contribution to society. It is observed on the first Monday in September in the U.S. and Canada. It was first celebrated in New York City on Sept. 5, 1882, under the sponsorship of the Knights of Labor. Various U.S. states observed the holiday before 1894, when Congress passed a bill making Labor Day a national holiday. It is often celebrated with parades and speeches, as well as political rallies, and the day is sometimes the official kickoff date for national political campaigns in the U.S. In most other countries, workers are honoured on May Day.