“The first Monday in September, is a creation of the labor movement and is dedicated to the social and economic achievements of American workers. It constitutes a yearly national tribute to the contributions workers have made to the strength, prosperity, and well-being of our country.” https://www.dol.gov/general/laborday/history
“In the late 1800s, at the height of the Industrial Revolution in the United States, the average American worked 12-hour days and seven-day weeks in order to eke out a basic living. Despite restrictions in some states, children as young as 5 or 6 toiled in mills, factories and mines across the country, earning a fraction of their adult counterparts’ wages. People of all ages, particularly the very poor and recent immigrants, often faced extremely unsafe working conditions, with insufficient access to fresh air, sanitary facilities and breaks. As manufacturing increasingly supplanted agriculture as the wellspring of American employment, labor unions, which had first appeared in the late 18th century, grew more prominent and vocal. They began organizing strikes and rallies to protest poor conditions and compel employers to renegotiate hours and pay.”
With the growth of the trade and labor unions the movement to celebrate labor began in the later part of the 1800s. Although the exact origins and the official founder of Labor Day is debated, its purpose was, and is, to recognize and celebrate this country’s laborers. Perhaps inspired by Canada’s annual May “labour day” celebration it is generally credited to one of two US labor leaders.
Some credit Peter J. McGuire, general secretary of the Brotherhood of Carpenters and Joiners and a co-founder of the American Federation of Labor, who on May 8, 1882 first suggested a day to honor those "who from rude nature have delved and carved all the grandeur we behold.".
Most credit Matthew Maguire who proposed the holiday later in 1882 while serving as secretary of the Central Labor Union in New York. The CLU adopted a Labor Day proposal and appointed a committee to plan a demonstration and picnic.
Whether it was Maguire or McGuire who first proposed the day, the first Labor Day celebration took place in 1882. In NYC, during the meeting of the General Assembly of the Knights of Labor, the Central Labor Union organized a “working men’s parade” and picnic to take place on September 5th. Over 10,000 persons participated in the parade although 30-40,000 marchers were anticipated.
"The parade...was conducted in an orderly and pleasant manner...Nearly all were well clothed, and some wore attire of fashionable cut...the working men were determined to show their numerical strength in order to satisfy the politicians of this City that they must not be trifled with...the orderly appearance of the men in line bore testimony to the fact that they demanded recognition as law abiding , peaceable citizens..." With the event considered a success Maguire proposed making this an annual event to be held on the first Monday in September and is generally considered the founder of Labor Day.
In 1887, Oregon became the first state to declare Labor Day a holiday followed by Colorado, Massachusetts, New Jersey and New York.
With labor unrest in the country several events led to the recognition of Labor Day as a federal holiday. The Haymarket riot was the aftermath of a bombing that took place at a labor demonstration on May 4, 1886, at Haymarket Square in Chicago which began as a peaceful rally in support of workers striking for an eight-hour work day. https://en.wikipedia.org/wiki/Haymarket_affair
On May 11, 1894, employees of the Pullman Palace Car Company in Chicago went on strike to protest wage cuts and the firing of union representatives. The American Railroad Union called for a boycott of all Pullman railway cars, crippling railroad traffic nationwide. To break the Pullman strike, the federal government dispatched troops to Chicago, unleashing a wave of riots that resulted in the deaths of more than a dozen workers. https://www.history.com/topics/holidays/labor-day-1
To read more about the Pullman strike visit https://www.history.com/news/labor-day-pullman-railway-strike-origins